OOB rates when bundle is still available

I received my Telkom Mobile statement for April on the 2nd of April 2015. Upon having a closer look, I noticed a R500 data usage charge on my bill. I called the call center to find out what the charges were for Nomvuselelo told me the charges pertained to OOB data usage. I have an Internet 5 Promo contract that gives me 10GB per month. I then requested the CDRs. Looking at the CDRs I could see that I was charged OOB rates between the 19/03/2015 and 23/03/2015 and then suddenly in bundle R0.00 rates return. When I queried this Nomvuselelo became impatient, and I asked for a manager. The manager then tells me it HAS to mean that I had no Telkom Mobile coverage, even though it shows full 3G coverage in my area on their coverage map. He can't provide evidence to substantiate this claim and my router is in the lounge where it has always stood for the last 3 years I've had this contract and this is the 1st time this has ever happened. After an hour ****erally) on the phone and no reasonable explanation, I either want credits or a concrete reason for these charges or I'll be visiting the consumer board.