Windows 10 sucks

I was offered Windows 10 earliervthis week. Accepted the download only to find that my computer has gone from an 8.1 system that operated perfectly to a computer that does not boot. Long story short. I now have to pay EUR100 to have my computer reset back to wondows 8.1. Computer repair man tells me that they are snowed under by Windows 10 problems. DONT UPGRADE YOU ARE LEFT TO COUNT THE COST YOURSELF