Possible to deactivate my license on a mac I no longer have?

Hi,

I used one of my 2 licenses (TechTool Pro 9.6.1) on a Mac that I was checking to see whether or not to buy. I ended up not buying it, and returned it to the owner. But realized I forgot to uninstall TechTool.

Is there anyway I can deactivate it from my own Mac or from here?

Thanks in advance for your help!