Erin, I am so sorry! What a bunch of crapola and very stressful. First of all, if they cash your check or accept the $30 then they are accepting to "terms", regardless of the state you are in. Once they accept that, few judges will want to meddle. Secondly, yes, they can actually proceed with a lawsuit because they want to move ahead with something called a "Summary Judgement" - this allows them to be awarded a piece of paper that allows them to collect on the debt if they feel you are not paying or not paying enough, by their book. BUT, that said, they are only able to legally be awarded for 25% of your net pay, based upon the past years' income or past 90 days unemployment. So, for instance, if 25% of your net pay over the past year would have equaled much more than $30.00 then they will be awarded that amount. But you CAN argue for hardship in front of the judge. If you are on any type of unemployment now, they can take up to 25% of each weekly check.
It sounds pretty negative and I'm sorry they are playing such hardball. The best thing you can do is pay them $30 as promised and if you do get a court Summons, keep a diary/journal of what you are doing to make ends meet and that you simply cannot pay more at this time. Most judges are fair when it comes to small debtor cases such as this - they can't bleed blood from a turnip - and if anything the judge may raise it to $50 but in mose cases, stuff like this will indeed favor the respondent (you) not the petitioner (them).