Not Updating/Poor Call Quality. HELP

[RiseAgainst94]

I was having some serious call quality issues for a about 6 months with my Lumia 900 (people said it was going in and out of being muffled and could barely hear me) so I chatted with a Nokia representative. We restarted my phone and what not, but the call quality issues were not resolved. He asked for my latest firmware number (2175.2301.8779.12223) and showed me that the latest version is SW 2175.2905.885x.124x0 (Nokia Lumia 900 Support - Nokia - USA). My phone is set to "notify me when I have an update" and I tried to force it through Zune, but to no avail. It seems my phone is not updating?! and the call quality is really terrible (used to be fine). My warranty literally ended a week ago -.- so do you guys have any advice on what to do now and how I can solve this issue? Thank you very much

Additional info: AT&T, 2nd device a refurb I got from Nokia after 1st device had problems with screen, I RESET my phone and same firmware with no available updates.