Supersonic fibre after sale service

I have a problem!!!! My rooter keeps on losing connection to the internet. I have phoned Sunday morning 22 Aug. It was fixed. Again on monday 23 Aug I had the same problem. It was fixed. On 26 Aug the same thing happened. I have asked the operator to report this. I have phoned the service line and requested a call back ... twice ... no reply!!!! Today, it is the 27th of August 21:00. I am still without internet access. They don't even bother to call back when I request so on the call center line.