La Zoccola in Amsterdam

Here is the story: they have a faulty payment terminal with a bad connection(and they admit they know it) so you may end up with a double payment and then you call them for a refund, they promise to refund in an hour, then few hours later you call again, they again promise and so on and on… this is surely not my fault, but somehow I need to chase them to get the money back, terrible irresponsible behaviour.