Umexplained billing

Hi. I have been a subscriber with altech autopage for years. I received my bill to pay and the amount is tripple x 3 what i normally do. I have phoned altech autopage to find out what this is for and they said they will log a query with the accounts department. To date i have mpt received a reply. I have received my bill and nothings been done. I am always connected to wifi and i do not do any downloads. I am not able to afford the amount charged but i will be paying my normal bill as per every month. I think that after bejng with them so long they will be keen to help but unfortunately its not the case.