There is a possibility that they will repossess your car unfortunately, as you have defaulted in the past, and that is what title loans and repo companies make their money doing!
Normally I would say that no, they will write to you first and ask you to make immediate payment but with this company I have heard of cases where they have come for someone right away, even following them across town.
I don't want to scare you, but this is a problem you need to address now. I don't believe they are the kind of company you can call and explain things to, they will have heard all the excuses before... even if they are true.
So is there any way you could borrow the money from family or a friend who may be more sympathetic? Otherwise, I would recommend seeking advice from a debt management professional or a governmental support line. You may even be illegible for emergency funding depending on your personal circumstances.
I really hope this works out for you.