I've been getting a load of collect calls over the last two weeks.

The caller only gives his first name and I refuse them.

Problem: I worked with someone by that name years back and we were pretty good firends. It sounds like him but I'm not positively sure it's him.

Aren't there scams where you get charged a load of bucks if you answer a collect call from an unknown caller?

What's the worst if I accept the call?

Poll to come!

IBTP!
Ultimately it's up to you.  You can accept the call, quickly ask what the individual's last name is, and if it is your friend, ask for his number and call him back.  If it is a mistake, "sorry man, name isn't familar. Please don't call here anymore. (click)"