Tips on making sure another Skype user can't avoid talking to me?

simply put, I gave money to a certain online merchant using a debit card. since they sent me a message saying to contact them I have attempted since last evening to get in touch with them by phone and Skype. their previous chattiness has disappeared and the “away from Skype” icon (not the gray one with the X, the green one with the clock) appears every time I try to reach them. I can’t think of what to do other than to create a new Skype account and try to reach them that way. any tips on this?