Have you contacted Sonos Support to speak with them about the issue?

They have more tools and insight to issues that users do here.

Burt it sounds like a hardware failure from what you are describing.

Sound like a hardware issue. I strong recommend to contact Sonos support via phone. 

I did they just said there is nothing they can do and to buy another…

Currently, SONOS does not offer any repair options in the US. There are some 3rd party repair options in the UK and EU. You can also find some DIY videos online. Note, however, a unit that has been disassembled is no longer eligible for any SONOS defective replacement discounts.