First you need to explain what you actually did, used a coin mixer maybe? Give us a little more information on what wallet you use, where your transactions come from, and then we can try to find out what the problem is. It may just be a problem in your wallet (not sync), so you don't see full balance, but you might also be scammed.
Edit :
This is the first time I've heard of this fake mixer - but OP is say that he is done many successful transactions, perhaps their modus operandi is to process small transactions, and then scam users when they send such big amount of coins