Takelot wallpaper falls short of the add

I ordered two rolls of wall paper which was advertised as 10m rolls, i received two rolls as ordered, the add says it is 0.45m x 10m. After using the first roll, i found that a roll contains only 5m and not 10m as advertised. I am very disappointed, the service up to receiving it was awesome, however, trying to find out why i received two rolls of 5m each where i ordered 10m rolls is proving to be an obstacle. I sent them a email to complain and promptly received a mail to say i must return the wall paper, how do i remove 5m of wall paper from my wall and send it back???? I dont want a refund, just the 10m paper i didnt receive!!!