Current Balance on my gophone account that I want refunded

I changed my gophone plan today from the 45$ plan to the 60$ plan for the purpose of having unlimited data. However there is a 20$ balance on my go phone account that I would like refunded to my credit card because I paid for the new plan with my debit card. I was under the impression I could use the 20$ balance on my account towards the new 60$ plan upgrade, but was informed by a associate that they can not even access my gophone account in the store. Is there any way I can get the 20$ account balance back on my credit card? I am already signed up for autopay so my next bill come directly from my debit card.