Paying for Telkom employee mistake

I took a phone in Oct 2015 and in Feb 2016 went to Tygervalley Telkom store, asked one of their employees to upgrade my data plan instead of upgrading the data she upgrade phone and data plan. I only found out when they send their bill and I opened a case. The case( ********** 3) was closed without solving it, I called telkom several time and explained to them what happening and they told me they will email the person who was working on my case and s/he will get back to me within 24 hrs now its been a month s/he have not get back to me.