In Internet there is a lot of scammers, but there is also people who really can unlock iCloud for high price. But there is some kind of scammers that mask themselves as good unlocking service. I’ll give you example to better understanding how they are doing that so you will understand and do not be scammed.
Scammer just find some good not cheap service that remove iCloud, for example for $140, next he offer his own service to unlock for $90. Yes, you hear that, he pay $50 more than receive. In this way he get trusted buyers feedbacks that really happy and unlocked. It makes other people think that he is not scammer and they become send money to him. This scammer takes money beforehand and receiving 10-20 orders that become pending. Once he understand that he received enough money, he just gone and you are scammed.
Have you thought ever why some people picking up nicknames that contains various of numbers and letters? This people never tell real name and they hide their details. You can tell me that it cool. Yes, maybe, but Scammers using that to hide themselves. Once they scam people, they just change nickname and use another one to scam more people.
I think you can trust people only if you can google his name and find real social profiles that alive long time already. In most cases even phone call not guaranteed that other person that you talking is not scammer. Believe only statistics, your eyes and facts, but not other people words.
There is also popular scammer method that they request only half of service payment, and other half after successful unlock. You will think that it nice and more trustable? Maybe it will confuse you and you will trust scammer. Just think about it, no one serious business based on paying half price before and half after. Since there is not only sellers scammers, but buyers also often trying to scam sellers. It will cause all sellers to loose more money than they earn. Just know that if someone request only half payment beforehand, they 99% chances is scammers.
Be careful, if you found some nice price source, or even if you have few proofs that it works, don’t believe to it in 100%. To become trust any seller you need first know that he already have a lot of feedbacks from different people in different time. Trust your money to other people only if you have exact information that makes you be sure in seller. With the temptation of low price also comes risk and disappointment.
Save your nerves and be careful in your decisions.