Not taking responsibility for product default

Bought a yamaha music cast system (3 speakers including a sound bar) from them towards the end of 2021. It all connects on your wifi network and they told me its super easy to operate. About 5 months after they installed it, non of the speakers were connecting. The technician send me instructions to reinstall but it was not working. Waited more than 2 weeks for him to come out (after one cancelled call out) and he admitted that he himself battled to get it reconnected, to the point that he wanted to take the sound bar back to the shop as he thought it was faulty. But he managed to get them connected. 2 weeks later - same problem. They dont want to take responsibility and want to blame my wifi network, funny thing as my entire house runs off the wifi network without ANY issues. Waiting for 3 days now for the manager or owner to call me