Pathetic Customer Service - Billing Erorr

I recently upgraded 2 iPhones at the Worcester Q Sqaure store on the same day. They were supposed to be on the same billing arrangement but some how the store managed to have 1 cellphone bill go off from my Absa bank account, but another one was loaded to a Capitec account that I do not own. This has caused my account to go into arrears and now I have to pay a “penalty fee” for their mistake. Also not worth phoning them as they don’t pick up their phones.