How often can my insurance compnay ask my doctor directly to fill out forms, I have been approved for ltd untill im 65 and every other month my doctor gets forms to be filled out. I also have to end up paying extra to have these forms filled out as the insurance company does not fully pay the full fee.

There is no set answer but typically it's every few months or a few times a year. In your case you've been approved to age 65 (I don't know how old you are now) so it's strange that they keep asking for the forms to be filled out. The practical issue is that if the forms are not completed you may get cut off so you have to weigh that alternative. You can inquire with the company why they need such frequent updates and perhaps speak with a manager and agree with them on how often the updates should be provided.