Vodacom Westgate Mall

I couldn’t pay my account for 3months and then last month I paid for the months I was owing, on the 25th of May I went to the store to pay they told me that I must pay R1100 which was confusing cause I normally pay R985 I was told that my account is in arrears. The consultant said she does know why my account is on arrears when I asked why & how she said I must call the head office, is your staff not trained?