Lack of service

I recently upgraded my contract and the amount of data I receive according to the contract and what I'm actually getting is incorrect. I am supposed tog et 500mb data for the month and 1gb data free for 3 months. Now my 500mb data expired within 5 days? to top it all off the airtime I had on, for which I paid, expires November. How is thi possible?? I paid for it and now you guys just want to take it away?? Ive been a loyal customer for 7 years and now I dont see the point anymore. The branch never pick up their phones as well, but cant answer their personal phones fast enough. This branch is really going down the dump and Im getting fed up with paying for service and not receiving any of it!