volume up, mute and volume down buttons are not working.

i am ready to go crazy. initial issue was volume up button was the only one that didn't work, took it to a tech place and they said it was a hardware issue and they couldn't find the piece. i went online and it seemed possible that it was a software issue. in the meantime Rogers (Canada) said it wasn't my phone because the ie number was different. i said they were sending me bills without any problem... anyways, I'm not suicidal but I'm inches from giving up and changing inept phone companies... and phone types. I am now beside myself as the 2nd tech company I went to seems to have made the mute and volume down buttons also inoperable. So, what's my next step?