I have been going to dstv walk -in from May,June,July send yesterday, one in randburg

I have been going to dstv walk -in from May,June,July send yesterday, one in randburg. They overcharging me and again they cancelled my router and I had 400GB data that will expire on the 13th of September .I have been trying to explain to them that I don't want top up but to continue using my remaining data.they made me believe that I'll still be able to access my data even if they cancel the service. But I can't