Sorry to hear your problem. If "crusinon2 is correct with option 1, I found no such feature for my device.. I purchased a PODHD500X and after 3 months of fighting with the house techs. I tried to duplicate the problem as you described with added issues. On mine, sometimes there was no volume depending on how i entered the bank and channel. If I touched the Volume knob, the Volume would drop or sometimes return to 100%, If I changed any setting and returned to the channel i could restore the tone at full volume. With detail instructions to duplicate the problem, I sent it back to line 6. The problem was resolved after repair techs had to send it through two departments for troubleshooting. They did not respond with corrective actions. I suggest you call the manufacturer, detail the problem and steps to duplicate the problem. Ask them for their position and then send it if it is under warranty.
I understand the frustration for the time without your equipment. It goes with the modern technical times.
l hope you can get it taken care of.