MONDO MTN POOR SERVICE!!!!

Gosh....I was called by a sales consultant at Mondo telling me about a simcard contract(MTN simcard) saying I'm going to pay R90.00 monthly,so I saw it as a bargain to pay R90.00 for a 4GB simcard,then I agreed to take the simcard and said they must debit it on the first of very month..The simcard was delivered on the 27 August 2020, funny enough they didn't debit it on October like they said they are going to start on October, till today they haven't debited their R90.00 and the invoice that I received few days back says I now owe Mondo R1015.00 for a sim card contract that I was told to to pay R90.00.... I've found their account on Instagram I've been sending the DM's so they haven't said anything to me ever since then...... So I've told them that I wont pay the R1015.00 they're telling me about because the simcard is no longer working and I dnt understand why I'm expected to pay this amount because we agreed on R90.00 for 4GB MTN data