Reverse data contract

Cell phone number *** ID *** On the 26 August 2020 around 01:00 i received a call from vodacom elite mobile offering me an upgrade for a 5gig for R99 I took it however on the 28 August I received the device and the data were 30gig day and 30 gig night not the 5gig we agree to. I phoned vodacom the same date to reverse and collet the device I was told they will reverse after they collected the device but upto today they haven't collected the device and the 60gig is on my phone I don't know what to do with it use it or not they don't want to reverse and I don't have the R330 to pay them at end of the month.