DO NOT ACCEPED CONTRACT WITH DSTV

I have two accounts with DSTV that I pay monthly, However a month ago I was contacted by DSTV sales call centre upselling a contract subscription instead of prepaid one, I made a partial payment of R800.00 for the premium and compact packages which wasn't sufficient to sustain me for the month. so I was disconnected but I immediately remitted the with R400.00 but they instead chosen to allocate the money to a contracted decoder without my permission when I contacted their call centre to enquire I've been informed there's nothing they can as the system is the one doing the allocations.