My dentist is saying it is too risky for more refinement (Photo)

I have had invisalign for about 3 months, the main goal was to straighten a tooth but after 3 months with the invisalign treatment am not happy with results at all i feel like my teeth haven’t moved at all and the dentist wouldn’t do anything about it he kept saying it is risky and that tooth can’t be straight but it sounds more like he is just not willing to do anything so i was wondering if it is true what he is saying?