Cell C - worst experience ever

My mom, SCM Stander, paid her cell-C account end August (as any month before) - until today they have not allocated the amount and suspended her account. We have sent numerous e-mails with the proof of payment attached, made quite a few calls, however, we are not getting any response. This has been going on since 8 September 2021. We went to a Cell C store on 25 September 2021 where they sent the proof of payment to the collections department. Still nothing. Each and every person we managed to speak to either told us to wait 24 hours, hanged up the call or told us to hold and then the call was cut before any feedback was given. Every time we phone you have to explain the whole story again - every time the same thing. No one calls back.