I have done of calling for jobs over the years and have had been hung up. You can ask the relay person not to announce that you re deaf--if relay person says have to, then hang up and call up another relay person.
If you have hearing friends or family members, you can ask them to help make the calls for you or take messages from the employers. Ive done this and it was more successful. You can ask the hearing friend/family for their permission to use their phone numbers on job applications so they can take messages for you.
If you have VPS (videophone) then do same thing, ask the relay person not to announce that you are deaf, etc. VPS is much faster and more accurate communication than tty (I know many deafies not have great english skills).
Good luch 
