If only 4 months left on the registration, then simply back ordering it is likely the way to go...
With that said, you could utilize the Whois Data Problem Report System (WDPRS) to your advantage ... here's what you do:
1. Visit
http://wdprs.internic.net/
2. Indicate what info is wrong, such as email, address, phone, etc; even a missing country code in the phone number is enough to file a legitimate report!
3. Place back order, if not already done.
4. Wait ...
The wait may not be that long either ... every registrar I've contacted so far has skirted my questions regarding their specific policy regarding Whois Data Problem Reports if the registrant doesn't respond.
In a nutshell, if the registrant doesn't respond in as little to 5 calendar days, their domain can be suspended; 15 calendar days it can be deleted! I guess ICANN figures people don't go on holiday ... 15 days and one can lose their domain!
Folks who think account passwords, registrar-lock, etc protects them are sorely mistaken ... the WDPRS is a huge security hole - some folks already use it to grab registered domains they desire.
Good luck ...
Ron