If a biopsy says no h.pylori then that means it's gone??? is it 100% reliable ?

100% doesn't exist: Nothing in medicine is 100%. It is very unlikely that a pathologist would miss H. pylori on a biopsy, but they are limited by where the biopsy is taken. Your GI doc has a great understanding of this and will take the biopsy result into consideration. If they still suspect H. pylori after the biopsy read, they will likely think they missed it and repeat.