Elite Mobile not so honest

Someone called me to upgrade my cell contracts. The line was faint and I had to ask the person to repeat himself more than once, also the so called manager. After the call I realised that the amount was incorrect and my upgrade would cost me R175.00 more. I immediately cancelled the ***** transaction. They then deducted R300 from my account, without my permission - said they got the account number from Vodacom.. Does not want to refund my R300.00 .