Do you have any friends or family who you could temporarily move in with? If you move everything out of the apartment and THEN try to sell it, I bet he would give up his tactics if he doesn't have YOU to bother. I mean, if it's all about bothering YOU and YOU aren't there....I think he'll give it up.

Especially if you can get your realtor to "drop" the information that you've already moved (maybe to another country??) and will not be returning.