Not allowed to use monthly airtime to make phonecalls

I have a uChoose Flexi plan with Vodacom. I get R200 of airtime every month which accumulated to over R1100 by now. While on a phone call with a Telkom representative for a fixed line (10213 number) I got cut off. When attempting to call again a voice message tells me "You have reached your call limit. Please recharge your account ..." I now also notice that I have a "Recharge Airtime" option displayed when I call up the USSD for airtime. This has a value of R0.02 I don't recharge my airtime. Why would I? So where does this come from and why can't I use my >R1000 monthly airtime to make this call?? I called up 111 and spoke to a lady that told me I can't use my airtime, I have to recharge. What the hell am I paying for airtime if I'm not allowed to use it?!