Vodacom charges Roaming when Roaming is OFF?????

I went to Kgalagadi Transfrontier park from the 31st October to 15th November 2019. Before I left, I made sure my roaming was still turned off as I have never turned it on since I received the phone. I never turned roaming on on previous phones either. During the entire time of my trip, I kept receiving sms's from Vodacom telling me about roaming......I found this odd as my roaming was off and when they sent sms's, the little R on top showed. So I again checked my roaming and it was still turned off. During this period of time, I also received a message or two from Tracker telling me my car is off the grid. I ignored the 1st message because I wasn't going to turn on roaming, but I did answer the second message as I thought, if it goes through, so be it and if not, so be it.

I then receive my Vodacom account and see that I have been billed for roaming sms's and roaming voice.....but my ROAMING was OFF and I NEVER accepted any Vodacom roaming offers that kept on pestering my phone