Probably not easy and would be very time consuming (especially if it more than 50), but to transfer the listings across I would simply view the unsold listings one by one with the other account (assuming you're using the same computer for both accounts, no idea about phones) and do a "sell similar" on each item.
Note that the photos don't show up when doing this (eBay doesn't like it if you "steal" other users' photos so they remove them from the listing tool - even if the other user happens to be the one and same) so you will have to reupload them. I had a similar problem in March when I had to stop over 200 Good 'til Cancelled (formerly Buy It Now) listings from relisting and charging me hundreds of $1.65 insertion fees, ended up with way too many unsold items and they dropped off after 60 days (I saved a cached version of the unsold page, prior to them disappearing, on my PC so the expired listing URLs would still work, which they do even after eBay removes them from the unsold list).
