The problem is when the payment companys are so big and so few, that 1 or 2 companies can basically shutdown an entire business themself (by removing their ability to be paid).

The solution is to use anti monopoly laws to break them up.

I don't think that companies should be forced to do something. What I instead want is for there to be enough competition in the market, such that no matter how terrible your views, there exists at least 1 one who will work with you.

And if there isn't enough competition in a market, then that's a problem.