To the best of my knowledge these are the contact details, hope this is helpful.
Contact Person:
Mr. anson chen 
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Upload your photo to attract more business! Company Name:Shenzhen Jmt Technology Co., Ltd. Street Address: B2606,Qunxingguangchang,Huaqiangbei,Futian District City: shenzhen Province/State: Guangdong Country/Region: China Zip:518000 Telephone:86-755-83762252 Mobile Phone: 13480820991 Fax: 86-755-83767727 Website:
http://www.jmt-tech.com
http://jmt-tech.en.alibaba.com
If you follow this link you'll find some MP3 / MP4 players that look very familiar, they probably acount for about 80% of those on offer on ebay (I warn you now though, if you payed alot for any of them, do yourself a favor and don't look at the wholesale pricing, it will make you cry )
MP3/MP4 PLAYER direct from China
Interestingly, it would appear that the Model M004B "Blue Cheap 4TH mp3 mp4 Mp5 Rmvb OGG Portable Digital Media Audio multimedia player fm radio TFT LCD PMP" was only ever optioned for 1GB, 2GB, 4GB, 8GB & 16GB
NO 32GB.
I too have one of these things, haven't really looked at it yet, went looking for a manual, found this thread and thought it may be advantagouse to get to some more info.
I should imagine the manufacturer really wouldn't apreciate their name being draged throught the mud and it wouldn't suprise me if they refused to supply them from now on.
I've got the ball rolling, now if you really want to stop these charicters, you know what to do and who to talk to
Hope this has been of some help.
Best wishes,
John
A.O.C.S.