These are both good suggestions, but I don't think this is what OP wants. OP wants the reverse of what these sites do.

For example, bitpay accepts bitcoins and turns it into fiat that you can withdraw, but I think the feature OP wants is to accept fiat and turn it into bitcoins he can withdraw.

Unfortunately OP, I don't believe there is any sites like the one you are looking for at the moment. The best thing to do would just to buy BTC with your fiat.