Shocking Service as usual

Have had contracts with CellC for about 10+ years now. For the first time Dec20 took a phone in for an insurance claim. Never heard anything from them. No emails,calls or sms. Followed up with store numerous times. Couple weeks back got told ph is back. When wanting to collect discovered was never repaired. They sent it back again. Now insurance full of stories and wanting a formal letter why it took us so long. Excuse me, which part? We paid insurance, took phone in. No reply. What exactly must we do? We just want the phone repaired that we paid for. Already cancelled one contract this month, next month next one and by Sep done with them.