No Call back - Stop SMS'ing me

I have called the *** number numerous times to request that they stop sending me sms' about my account that is up to date which the call centre confirms. I am now getting messages that my account is going to be suspended. All line managers are not available to handle the query and none of the support staff know what to do. They promise to call back but never do or transfer the call to the incorrect extension. This poor level of service is extremely frustrating. Please can someone contact me as promised!