Will i ever be able to be sensing scales and notes ?

I am a vocalist in an extreme metal band. But now i m more towards clean singing. But the guitarist of my band (who has been playing guitar for more than 15 years) says that 'i do growling in scale but when its about clean singing, i dont maintain scale and this happens because i cant sense the notes ! '. He also says that the ability of singing perfect note is "god gifted." I had done some classes to a music teacher but he never said anything like that not even a friend who is doing classical music rather he says that my guitarist is stupid and it takes a lot of practice and time to be able to do such thing. My guitarist is a much experienced musician. Should i really accept his comment and give up the hope to clean singing or should i practice like hell and see the result. Well, his comnent is more like depressing me