What should i do if my 6 month baby does not want to drink any form of formula?

Transition slowly: Breast milk tastes radically different from formula, and babies get used to what they have been on. I'm assuming that you pump and feed with a bottle, and if not, start. You can start by adding 3/4 breast milk and 1/4 formula to a bottle and starting that for a week or so. Then slowly transitioning to 1/2 of each, and eventually working breast milk out of the bottle entirely.

Try a Cup: In your comment, you mentioned bottle difficulty. Why not go straight to cup. No reason not to.