WebAfrica services is really poor

I requested WebAfrica to downgrade my package from R529 to R399 that was on the 12th of October 2022 via their WhatsApp service and I was told that by the 1st of November 2022 they will debit R399. Yesterday (01/11/22) they debited R529 instead of the R399 we agreed on. I had a chat with one of their agent (Tiyane) he/she said unfortunately I was misinformed by the previous agent (Milton), I should have logged in on customer zone, I told Tiyane I don't work for WebAfrica I thought the WhatsApp service would have assisted me. Tiyane said unfortunately there's nothing he/ she can do, now I won't have transport fare in 2 weeks time because of them putting me out of budget. I'm really disappointed by the service of WebAfrica and I'm considering changing them, this is uncalled for and unprofessional