It can be your experience in buying online service on cryptocurrency and you should learn from this accident so that it won't happen again next time, as @MiguelCryptoss suggested before in this case you have to use escrow service to buy anything online from other for not to be scammed again.
BTW, how many BTC was you sent for his service? And can you show us the txhash of your transaction as proof here?
Edit:
I have tried to search that username on the forum maybe he has an account here, at the end I found it
"The Modern Investor" but it seems he just register an account here and never use the account for any activity