Taking money from my account

I noticed on my bank statement this month that Vodacom took R29 from my account on the 12th,16th,23rd and 25th of March 2015. I no longer use Vodacom I have switched to Telkom Mobile so I don't receive or use any of this airtime.I called Vodacom on the 30th of March to find out what was going on I was then told to email customer services my monthly statement so that they could figure out what was going on and I did that immediately I haven't heard a word from Vodacom since meanwhile my account has been frozen. I would really appreciate it if Vodaom could sort out this issue for me as soon as possible