Appstle Loyalty Reward Program

Support / Devs can't solve bad styling issues in their words due to our custom CSS in our standard theme and want us to remove our CSS that makes our site look fantastic due to their app using the same ID's needless to say we are not impressed with Appstle. We should not have to change our industry leading site to fit their app. It should be the other way around.
They have 14 days to change their mind and find a solution on their side or we will delete their app and look for a competent app provider. They have been paid over $500 so far, this is not how to treat paying customers!