do it by yourself to change plan go use browser from computer,and clear cache and cookies and use one page inPrivate mode,or safari on private mode,To Login Page
and go to Plan & Add-ons, and scroll the plans using the down and up arrows on the far right. select the plan you want, and select ‘Change plan now’ then you pay full price plan, or ‘Change plan on renewal date’..to you not losing any money..
if still can't changed then contact PM support team by CS_Agent
@sartajkhan problem with changing plan?? you can do it without talking to agent. Just login to My Account, go to Plan and addon page and click Change my plan. Use the yellow arrows on the far right , or at the bottom for mobile site, to scroll through the plans and select the one you like
let us know if there is any problem