Unable to switch Plans at Jet

I currently have a Jet/Edgars account on a 12month plan. The 12month plan incurs interest. Therefore, I decided I wanted to switch to a 6month plan which does not incur interest. To my surprise, when I called the Jet Customer CareLine I was told that I could not switch from a 12month plan to a 6month plan. The agent said customers were only allowed to switch from a 6month plan to a 12month plan but not vice versa. When I asked why, the agent simply said "its company decision". Unfortunately I did not get her name but this is pathetic. Customers must have the freedom to choose whatever plan they want and switch anytime. I'm now considering closing the account. Pathetic service from Jet/Edgars.