Total disregard to ********** activity

My mom, who is a pensioner has complained numerous times at your Town Centre Branch in Mitchell's Plain without receiving feedback or a resolution. Her account has been charged with numerous Cell C vouchers since last year. Some months as many as 10 times. These purchases were not made by her. She complained at the store and was promised feedback however no one has ever contacted her. Please can someone assist in resolving this matter. It's really disappointing that this has gone on for so long. From what I can gather, the transactions date back to May last year.