First thing to do is pay it, that will help
If you talk to the collection agency and promise payment, good chance the credit reporting bureaus will not even know it. And for $30.00, they just want it off the books
If it has not gone to court and there was no judgment, then the reporting bureaus do not even know it yet, they will only know if the collection company turns it in, so call them NOW and get it paid off
If by chance they do turn it in, you are entitled to add a statement of explanation that has to be shown to any company that runs your credit, and for $30.00 it is an obvious error, not intentional.