no call back within 50 days

I have faxed a insurance claim from the mtn store in parow centre mall on the14/06/2015. they promised me a callback from the offices, . a month went by, still no call back.<br> I went back to the store 2 more times, I already have a new reference number, they promised me call back in 3 days and still nothing, my patients are running out and I don't know who to go to to speed up the process, it seems they just don't offer proper assistance when it comes to my matter specifically. also they do not pick up the telephone on the lower level mtn, I have been trying to call them for about 2 weeks. I need someone on higher level management to acyually action my querie, I have been a loyal customer and been paying my insurance but now when I have claimed.. nothing is being done.