VODACOM CLAIMS MONEY OFF MY BALANCE

I had a Vodacom uChoose Flexi contract which was past its expiry date. I had about approx R2000 on the phone as I did not use it becasue I left the country and totally forgot about this debit order (my bad). The service was cut off which is fair enough, but the R2000 credit that was paid for in prior months before that was also wiped off my account. I have asked continuously for over a year now, if the value they have wiped that I have paid for will be refunded or re-loaded (as I did pay for it) but everyone just ignores this and now Vodacom wants to issue a summons? Once I pay this bill, will I be entitled top the credit I had before they wiped it off my phone and cut off my service, surely if I have paid for it, they can't take it back?