Canceling a sale

[scrunchdogg]

I received a email from the buyer that due to personal reasons with there Mother they need to cancel the order. I had a unpaid case open on her but after receiving this message I closed the case. Now I'm trying to cancel the order but I keep getting a page that tells me I cant because there is a case open. I was able to relist it though so I don't understand why I cant cancel.