Refund

I paid R1587 on the 2nd of January for 3 routers. 2 of the routers were mistakenly canceled and I immediately revoked the cancelation request on both. When I enquire about a refund I'm told that I am on a post payment plan. How? You don't even get a router without paying upfront and you disconnect if payment isn't done for that month. Now, I want a refund of R1060 for those 2 subscriptions otherwise I'm not giving the old routers back.