Not fixing a problem in 8 weeks

My Marantz amp has not been able to airplay for over 8 weeks. The supplier has come out to fix it and assured me that it is my router and not my amp. I have asked them to replace the rooter, but they are too busy to help. They also let me know, that no one else can sort it out and they need to sort it out, but are fully booked until February. A week ago they would have called me back in half an hour to schedule the appointment. I still have had no reply after numerous calls and sms's. I opted to buy a quality product, but this R25 000 system is still not working. I have never spent so much money on something causing me so much hassle and I am desperately questioning my decision to do so.