assistance needed

Good day

Has anyone experienced any problems with MTN when purchasing a product online? i purchased a router service, i returned the router in the first 10 days, and phoned in to cancel the account, i have since been debitted of R3000. and can never get hold of customer service.. is there perhaps anyone that can assist ? i have been into the MTN branch, they cannot assist me as they say it was done online, and MOMO rewards are a separate branch.