I WANT MY R240 BACK

i had a contract with the company for 24moths. skipped some payments but managed to be up to date and decided to close the account. i called in for the balance and cancellation fees. i was then given the total balance of everything. i went to the bank (last year December) to make the deposit but i made some calculation errors while depositing, i made an over payment of R250 from the balance due. i tried to call the call center but i was told i still owe money. about two weeks back i went to the store where i signed the contract in lephalale and requested a print out of everything, it clearly showed -R240 (interpreted as money owed to me). I WANT MY R240 BACK.