This is a total scam, do not follow their instructions, their is no legitimate company that will "see" malware ("junks" as he called it) on your computer and phone you about it.

Any clue where this is from?

Had a phone call saying that my computer was downloading malware and they could fix it.Gave me the obove telephone number and e.lmail address dech @ onlinesupportpc.com

this phone ring 10 times a day in evening

This is a scam artist wanting to install malware on your computer.