DATA USAGE / INCORRECT BILLING AGAIN

Dear Vodacom Business , Please can you help. I have received my bill today for excess data on *** for a R1000 extra data. My phone does not allow this and has never been this high. Something is wrong. When I called this morning you service centre said that I have once again gone over my limit. and then after checking said oops I actually have 1.6gb left yet you are still billing me out of bundle rates. PLEASE CAN YOU CHECK THIS. My phone blocks at 2 gigs. Please this is going on and on and I need some resolve. You also sent me a sms this morning saying I had 1.6 gig left this am yet now your centre says im over the limit. DOES NOT MAKE SENSE. Something is not right since my upgrade in January. PLEASE ADVISE URGENTLY , I would appreciate this being resolved. REF NO WYNU-16L352