over charging and supplying false information

I never had a problem with my monthly billings on my previous contract until i recently got an upgraded. I was over charged on mobile data of R273.12 which i never even went over board with my monthly data that i get accordingly to my contract of 200MB. I phoned and complained about this over charging which they told me i would be refunded that amount back in full. I then got a sms saying that my credit was approved but only R125 and i would like to know why not the full amount as promised. I then phoned them back on the weekend which they told me they cant help me as no one works in the accounts department on weekends. The lady then told me i have no airtime left but when i checked on my cell phone it showed me that i have R151.20 left remaining. i NEVER had a problem with this until i got my upgrade. I expect a phone call with a good enough explanation and i will not recommend Altech Autopay to anyone.