Spam from Thai Company

The Company Perfect Training and Services, http://www.perfecttrainingandservice.com/ is sending unsolicited emails to different email accounts on my company domain. The so called Newsletter is complete in Thai and does not include a Link to be removed from the Mailing List. In addition nobody did apply to this mailing list.

I personally sent a few emails to ask them to remove us, but we still receive this unwanted emails. A research brought following result:

The IP Address of the company website is located in Canada, but the Domain Space Provider is a Thai Company called Dragon High Speed. Their Website is www.dragonhispeed.com and it is existing, but the there used contact email address, info@dragonhispeed.com, is not working. A WHOIS search resulted in an other Contact email, admin@dragonhighspeed.com, but this is also not working.
(There is no spelling mistake in the above email addresses, there are written this way, but both are bouncing back.)

A whois.net search showed details Administrative, Technical and Billing Contact, which is Mr. Jerat Wattanakool, dreamhorror@hotmail.com. This email address was also contacted by me requesting a remove of my Domain from there email lists. The email did not bounce back, but there was no answer.