Update on my cell phone.. CRAZY RANT

So we ended up waiting to go to get cell phones because we cant renew our 2 year contract so we would hva epaid a no committment price for a phone which would have been ALOT of money.. I called customer AT&T customer service and asked if our coverage for the 3G was working in our area and the guy told me no and gave me a number to call to find out why its no longer working in our area. I end up back to the same place talking to a different guy who tells me I DO have coverage and he did not know why the other guy told me I did not. He had me on the phone for literally 48 minutes  trying different things.. take battery out put it in.. etc.. over and over.. NOTHING WORKED So they put me through to technical support who asked a few questions about my phone.. had me push a few numbers and read a code.. then he tells me to call my voicemail to make sure I can get a call out.. I try and all a sudden NOW my sims card reads unregistered.. It was just working just fine a few minutes ago and NOW THAT is BROKE! I WAS SOOO MAD! So since its now not working we can not continue to fix  the problem of me not being able to connect to the media net anymore which means I can not not send pic texts! So he tells me I need to go get a new SIMS card and he will put  note on my account for me to be able to do this. So problem STILL not solved other than he just says it my device thats not working. So.. I put my husbands SIM card in my phone today and went to my aunts house in a different town and WALL AAAA .. MY PHONE SENT A PIC TEXT FINALLY! SO that means it is NOT my phone! ITS THEIR SERVICE!!! I am going tomorrow to a corporate store and getting this crap taken care of once and for all! That was the 2nd time I was on the phone for over an hour and nothing got resolved! Both LONG calls ended with try a new sims card.. W/E  Not the card now I know for sure!!!