the resolution centre is not working,what do i do

i have been asked to cancel 2 purchases that were made by mistake. the resolution centre will not let me take action. this happened to me a while ago. i asked a buyer to accept a cancellation and the buyer had the same problem, she could not get the computor to accept the cancellation. eventually i closed the action and was refused final value fees.  what should i do about cancelling these 2 purchases. thank you  chris