As others have mentioned, more details will help.
Some anecdotal stuff: Name of shops as well as the area you were trying to p4p. I've heard horror stories of colleagues from my country. I asked them where they went and they said Kabukicho and Ikebukuro. I asked why didn't they go to the most famous area - Yoshiwara (it's been around since the early 1600s), they said they never heard of it and only read about Kabukicho.
Personal thought: Is Yoshiwara really that much less famous to foreigners compared to Kabukicho despite the former's much longer history?
Back on topic, like all things in life - success is determined by preparation and opportunity. Whether you're going for holiday, seeking a job, or p4p:
(1) Know what you want (the generalities). This means having clear goals (e.g. I want CFS, BBBJ, and I'm prepared to pay XYZ at most). Know where to go to get it, want to say, what to do, what to avoid. Yes, this means you need to study (read reviews, compare areas, think hard about what you want). I don't know, I guess the educational system in many countries leave a bad taste in many people's mouths. If you want a higher success rate in p4p, at least put on your thinking cap (on the big head on top, you can cap the other head later before you insert it).
(2) Plan, plan and plan (the details). How are you going to get to the shop? Example: If you place to take the Hibiya subway line to Minowa station and walk from there, are you going to look at your phone all the time? That's going to give you away as an unsure foreigner. We're already playing with a disadvantage as a foreigner, at least be confident by planning properly.
During my first time to yoshiwara, my plan was to exit Minowa station by exit 1a, head to junction 306 (straight from the exit) which is a crossroads, to my right is a McDonalds, turn right and keep walking straight (10-20 minutes depending on your walking speed) until I see a fire station(東京消防庁日本堤消防署) beside me on my right, immediately after that turn right and walk down a short distance (3-5 minutes), I will have reached Hishoshitsu (a SL recommended on this forum), and thus know that I'm in Yoshiwara. Notice that I mentally noted landmarks and directions, minimised twists and turns, never needing to check my phone the whole time. Of course there are faster ways if you know how to cut through the various side streets/alleys, but don't make it harder on yourself during the first visit.
Regarding the provider, try to check city heaven, playgirl.ne.jp, 26style, or her twitter (<shop name> <space> <provider's name>). Copy and paste is your friend if you have no Japanese language ability. Read, read and read, then think, think and think. This reduces (but does not eliminate) the chance of a 地雷嬢 (i.e. stepping on a land mine). Some accept first time bookings from DMs, others mention in their bio/profile that first time customers should book through the shop instead - if you can't read Japanese, google translate is your friend.
(3) Execution of the plan and contingencies. If you didn't reserve time with a specific provider, be prepared that she may not be available.
Regarding the shop, if offered girl(s) that you don't like: are you going to settle and pick one or do you plan or giving a quite apology and leaving?
Sometimes the male staff of the shop offer a very narrow selection to first time customers (especially foreigners), even though many of the girls are "grinding tea". Do you plan to be assert a little, and politely ask if so-and-so is available if you'd followed point 2 above and checked the girl's schedule, she might be free? This might pay off, or might backfire - hence the need to have contingencies, what have you pre-planned?
Regarding the actual play: Do you plan to be "dead fish" and let the provider service you? Are you well hung and possibly have trouble inserting into her? What are you going to do then? How do you intend to communicate with the provider?
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You've probably noticed by now that I see p4p as having a key intellectual aspect, the planning starts weeks before arriving in Japan, and I mean a concrete, well thought out plan with fallbacks. Yes, we are all seeking pleasures of the flesh, but the more you're willing to use your big head on top, the higher the chance of success you'll have getting pleasure with your other head down there.
The reason I typed so much is because:
(i) You mentioned getting scammed multiple times, this screams of no/insufficient planning. Even when going on holiday to enjoy, please do study on the customs, local culture, public transportation, social faux pas, and a bit of the language a few weeks before if possible. I've seen so many people balk at studying, then struggle with this or that when they arrive and get so stressed just trying to buy pocky at Haneda's airport duty free shop.
Sidenote: In the end, I told the lady: if you can't speak Japanese, just google a picture and show the staff. The reply was "that's so clever, I never thought of that!" ... No madam, that isn't clever, it's called common sense as "a picture speaks a thousand words". Speaking English slower to someone who seems to have trouble understanding any English at all is unlikely to help.
(ii) Lack of details, so I'm throwing out what I can think of right now, since I might not check the forums for a week due to the festive season.
