unresovled data issue

I loaded an extra 2gb data bundle on the 13th of November and noticed I was still being charged for data. I called the Melrose Arch branch as they are the ones who loaded the data bundle for me and was told that it has been loaded and shouldn't be charged and they will send query to head office to arrange credit. after sending a number queries through myself head office eventually called me and said I cant have 2 data bundle packages in the same month as I already have a 500mb one and would only be effective 1 December. When I told them no one informed me of this they said they cant do anything and must take it up with the store. The feedback I got from the store was that the person I dealt with has since resigned and there was no way of working out what happened. This is totally unacceptable and really not my problem. I have been a customer for over 17 years and this treatment is unacceptable. Unfortunately I still have 8 months left on my contract but trust me after that will not be renewing with Autopage.