Every 15 mins I contacted the support staff to follow up on the credit addition, and each time they said 5-10 more minutes

I work as an inbound customer service rep and this more often than not will either delay the resolution of your case or accomplish nothing but wasting your time.

I don't know how Skip's credit system works, but it sounds similar to where I work and it's usually just a matter of the system updating for it to either allow you to reuse the code or apply a credit for the equivalent amount to your account. Not usually a lot the agents can do about it as they are bound by internal policies and procedures first and foremost.

But yeah, Skip is pretty bad.