Changes out batteries blew 100amp fuse changed batt and fuse didnt start or blow

I was at work so what I was told was that a good battery was put in my car and it started right up while it was still running they took out the good battery and put my dead battery in and then it died and blew the 100a straight male terminal. I know nothing about all this.

Who is 'they'? , a shop? While it was running and they removed the battery the positve cable probably touched ground and blew the 100 amp main fuse , maybe it blew some other fuses also , just prior to the main fuse.Maybe reduce further risk and cost by having it towed to a more qualified shop.