Music Man Majesty Sound Issues

I had an issue while recording with my Music Man Majesty 7 string (Arctic Dream), for some reason the sound abruptly stopped while playing it. Only if I unplug the cable, plug it back in and hold down the piezo volume knob I have sound until I let it off. I already tried the 10 second hold, changed batteries and all that stuff and only have sound if I hold the piezo knob. I don’t know what to do anymore. I bought the guitar in June 2018 from Sweetwater while in US, I’m currently living in Brazil and already contacted a local dealer (Royal Music) who told me that cannot do anything unless Ernie Ball send them instructions. Already sent en email to EBMM Customer Service but so far no response at all!