Alien M18x - Logitech Keyboard MK710 stopped working

• Keyboard was bought in 5 November 2012 with Alien computer.
• It has self disconnected today.
• Batteries icon flashing.
•  Installed latest Logitech unifying software - unpaired and paired again(mouse) - can't detect keyboard now at all.
• Installed new batteries.
• Tried switching on and off.
• Tried removing batteries and waiting couple minutes. 
• Tried replacing batteries (Duracell) again.
• Tried on other USB port.
• Tried on other computer.
• Tried rebooting computer.
• I've been working in computer industry since 1998, so please don't ask simple questions.
• Followed instructions http://logitech-en-amr.custhelp.com/app/answers/detail/a_id/14293/section/troubleshoot/crid/433/lt_product_id/6541/tabs/1,3,2,4,5/cl/us,en
• And forum http://forums.logitech.com/t5/Keyboards-and-Keyboard-Mice/MK710-Combo-Mouse-Working-but-keyboard-not/td-p/531226/page/3.

 NOTHING HELPED. WHERE TO SEND BACK MY KEYBOARD AND MOUSE (in the UK)? Thank you in advance!