My suggestion would be to contact your DMV and ask them to provide paperwork showing that the bike is no longer registered in your name. It'll likely have to be notarized which will be difficult if you're not in the US. You might get a family member to pick it up and then mail it to you. It's a tough position and happened to a friend last year. Eventually, after having his DMV fax paperwork to him which he had notarized on the US side, he was able to get in even though it really wasn't the correct procedure.
PHX AZ USA