> I was paying my debts monthly, barely, that wasn't good enough for one of the lenders and they sued me in small claims.
I'm sorry but there is definitely information missing here. If you were making the full minimum payment you wouldn't be sued, ever. If you were paying less than the minimum then you weren't actually "paying your debts monthly."
> I never got the summons (apparently quite common)
I can't speak to how common something like this is but you do typically need to be served with the summons, or the plaintiff needs to show some sort of proof that you received the notice (e.g. a certified mail receipt or statement from a process server that you were indeed served). But I can say it's not the first time I've heard of someone being unaware of a court date so who knows.