VISA gift cards promised

Was promised $300 VISA gift card and have received $100. Employee who signed us up has been no help, calling "customer service" has been a waste of time...three calls and on hold over 2 hours - on 4th call right now...on hold again. Website no help at all. So do I just give up? Do I give up and rip AT&T at every chance I get for people to avoid? Also, bill is $20+ more a month than stated during set up.