Am I being ****med?!!

I got laptop and a cell phone on contract though not at the same month, every month I keep seeing my premiums gradually increase and last time I check there is no agreement on the contracts that I have with vodacom where I agreed with them that my premium must keep increasing every month, I do not owe vodacom a single cent and I have never skipped even a month with my payments, am I being ****med here?