Telkom free airtime a ****

I recently bought a Telkom 20g free me bundles and was given 500 free airtime which I could use to make calls to other networks, send smses and so forth and this airtime is used before any other airtime and voice Bundles. I then realised that my bundles were being used up and not the free airtime. When I enquired with Telkom, I was taken back and forth, being given several different stories as to why I cannot use my airtime up until it expired.

They promise you free airtime knowing very well that you won't be able to use it, so annoyed.