Best course of action I've found, is to build your initial MVP with one payment provider but as soon as you've validated there is a market and before you move on with other features, add a backup provider you can switch to at any time because chances are you will get blocked at one point. If not permanent, at least temporary.
If you're clever enough when you build the initial integration, you make sure to abstract out the specific payment provider so it's easy to plug in a new one. Shouldn't add too much complexity.
Sucks but the reality we live in...