no response to hospital cash back plan claim

I have a hospital cash back plan with old mutual .I sent a claim over 3 months ago and haven't received a response to date, I've tried calling countless times to check how far they are and was told a lady by the name if Mandisa was assessing it but whenever I try contacting her the phone us never answered is I'm told she will call me back which they never do. I don't know what to do anymore because nobody from old mutual seams to be if any assistance regarding my claim.