Once Again i was not credited with the promised data

I cannot believe that almost every two months I have to do this, I was promised 2 gb of data I received it for a month then it fell off, I then had to write again and received a call from a very helpful Ula Wiggins but guess what my data fell off again, please can we get this right I cannot be doing this all the time if you guys make a promise .....keep it, I made a promise to pay you guys every month for all 6 of my contracts and in over 20 years I have not defaulted once you can check your records. please sort out this mess I am done with Vodacom.