No response from Telkom, bad service!!!

On the 10th of Oct my wife did an upgrade for my daughter at Telkom Mobile Keywest. The lady Raluoma assisted them with the upgrade and explained that the contract is 36 months and repayments will be R 734.35 on the Samsung Galaxy Flip Z 7, but before they could continue they need authorisation from Head Office as the phone is more than R20000. On the 21st of Oct my daughter received an sms saying "Dear Customer your subscription was successfully updated". They went to Telkom Mobile Keywest to find out what that could be for on the 22nd of Oct and the same lady said that Telkom now want them to pay the once off R20000 amount for the phone. She then logged a query on the 23rd of Oct to the billing department with reference ***9 to solve the issue, but since then we have not received any further assistance on the case. The lady is also not coming back to my wife with feedback ad expect us to call the Call Centre which we tried without any success. My wife signed a contract on the day for 36 months, how is it possible to expect a R20000 once off payment by signing a contract????