Complaint Office 365 Purchase not working

I have tried to get in touch with seller Tech by Mark in order for him to assist with my office 365 not working.

Reason being, my hardrive crashed and have had to replace it. So after I replaced hardrive on same computer

I could not re_install the office 365 software I purchased.

Seller Mark--> ***, ***, does not and will not answer your messages, phone calls or wattsapps and offers no after-sale service whatso ever. BE WARNED!! YOU WILL MOST PROBABLY LOSE YOUR INVESTMENT...