Billed five times for their own mistake

On the27 of may i sent a request to be downgraded from 4G unlimited (R479) to 4G unlimited peak (R250) before a new month starts so that that i don't get billed for 2 plans on the end of june. I did not get any response at all, but after the new month started i decided to keep the 4G unlimted, but on the 17th of June they decided to now respond to my almost 3 weeks old request, they automatically downgraded me without a notification. I then logged another request to keep my 4G unlimited but for the whole day i did not get a response, i decided to upgrade it on their website (you can upgrade but not downgrade). later Sahufa Sheik mailed me to as if i still need help, i explained that got downgraded and i upgraded it myself, also alerted to him/her that i shouldn't be billed for 2 plans because of their lack of timely response but the bill now is R2832.47. more than 5 times the R479.