Mistake on account costing me money

I went to this store to do a new contract at first the service was perfect. That same day we asked the sales person how do we pay he then promised that he would whatsapp the detail to me a week went pass where I did not received anything I went back to him he promised me it will happen still nothing one Sunday me and my wife went in and asked him what is wrong he then printed a old invoice with he could have done that first day. So we went home a few days before the debit order went off I went in just to my surprise the amount t was R998. The manager promised me it would be fixed but it was not he the amount was the same He then took R200 and went to pick n pay liquor to pay the 20th come and the full R998 was deducted my question what happened