Showmax makes it hard for me to UPGRADE my package

Showmax Makes it really terrible for me to upgrade from the Mobile plan for 39.00 to 99r option I spoke to 2 agents from the Live chat however I only have 1 name Kamogelo R that sent me a link https://secure.showmax.com/v154.4/website/profile/payments This link she gave me takes me to the option to upgrade to Showmax pro for 299 which I do not want to have I want the 99R option . When I select the 99 option it takes me to start the 14 days trial again ? Why must I start the trial again when I am already a Customer , Furthermore when I selected to start the trail again it asked me for my banking details and to pay 0.00 when I pay via the secure site it give me an Error ... Why is it so hard to upgrade ??????