Question About Youtube Subscribers

I've tried in the past to do sub 4 sub but all I get is people not fulfilling their end of the deal and staying subscribing to me. Can anyone suggest to me a good site for this?

Sub 4 sub has never worked and never will simply because everyone has the same goal.
You look for active "watchers/viewers", same goes for everyone.
It's a natural thing, if you are good at something or if you are providing value to other people will subscribe, other than that...
Do you look for SMM panels or?