The only way you can accelerate a transaction is through mining btc yourself and you are able to get blocks yourself. Which means, if OP is able to offer this service, then it means he either has that much miners or he's just using other services that accelerate the transaction. I don't think he has that much miners, since if he did he's wasting time doing this as profits from mining are way more attractive than wasting time asking people to accelerate through his service.

Just want to list two free ones I know of,

Viabtc
Antpool

Either he is using the free ones or he using the paid one from https://pushtx.btc.com/, however since the fees there are nowhere near cheap, then likely if he is using that service then he's carding.