Don't just be polite, get the job done - Ineffective customer service

I app**** for new landline for my mother on 12 January. My mother is 92 years old and has just moved into a new retirement home. When I app**** at Cresta. I was told 7 to 10 working days. When I checked to find out the progress one week later, I was told that the application had been put on hold, apparently my mother did not pass the credit check. SHE IS 92YEARS OLD! So, I went back to the Telkom Shop in Cresta, and the original sales agent and deputy manager put through an expedited order, assuring me that the phone would be installed within 2 to 3 working days. After sending several emails to check on progress, this was the response on the 6th working day: "the order has moved along to scheduling for an installation date. You will receive an sms". That was two days ago. I am fed up , my mother urgently needs a landline, what do I have to do to get Telkom to do their job?