Pathetic after sales service

I had a petrol pump installed on 17 September 2022. Soon after I realised that my petrol gauge does not work any more because even if you fill up the car the gauge remains standing just below the half full mark. I called and emailed to lodge my issue. The mechanic came through and did his testing to assess if the pump is faulty. He could not pickup any fault and advised me to fill up and drive around for the coming few days to see if anything changes. I travelled long distances on 24 September, car was filled up to full. Gauge did not move. Drove to and from Newcastle KZN and still the gauge remained on the same level just below half mark. I called and emailed once again to request the petrol pump replacement as it is clear the floating device on the petrol pump is not working. I have been promised that a mechanic will call and arrange to come. Initially he never called or show up, this was for the whole month of October, I would call every two or three days to ask on the status. I was promised he will call & confirming two weeks ago, he called on Thursday 03 November to arrange to come on Friday 04th or Saturday 05 November. I agreed to both dates to make myself available. Friday came, no call no show. Saturday came same thing. No show & no call to cancel or let me know me know if there was any problem with honouring the appointment. To date no one has called to explain what happened or what will happen going forward. I must pick up the phone and find out myself. Sadly there was hard earned money paid for this despicable service. I have paid for pathetic service and a faulty pump which totally defeats the purpose. I wanted to avoid mechanical problems by replacing what was recommended but now I am in a much worse condition than I was before requesting and paying for THIS. How am I expected to drive around with a car not being able to detect the level of my petrol tank? My patience has been tested for almost two months. This is totally ridiculous and unacceptable.