Hey, I'm sorry that that happened to you. If you are looking for advice, I would make sure that in written form you are making sure each person is aware you may have a stutter for every interview. It could be that managing expectations could help, however I do feel for you mate that it's hella annoying and people should just not be asshats. Good luck, and keep your chin up. You have a gift with writing, keep plugging away and someone will hire you.