Billed incorrectly and they wont refund me

So medshield makes a mistake a bills me for someone who has the same surname as me for a medical aid from my employer, this was in November. I have been explaining to them that I don't have a medical aid with them have never had a medical aid with them but that doesn't seem to get through to anyone.<br> <br> I have sent proof that they deducted money from the wrong person but over 6 weeks later I still don't have my money back, this is almost R2000 that we are talking about. can I have this sorted out as in yesterday.