Taking our money for free again

Got a open data contract, Asked them to put a R5000 limit on the usage, Jan 2014 they hit me with R10000 account. I phone them, they throw the phone down in your ear, i email them, no response a year later, Same thing right now , my account is over R5000 already no notice, no sms. They also do not want to give me the option to upgrade my contract to a top up.