"Am I actually required to foresee all my mistakes?
If you don't want to pay the printer for fixing your files, you are not only required to see all your mistakes, but you are also required to fix ALL of them before sending the files to the printer.
And to be able to (fore)see and fix all your mistakes, there is a very useful and efficient solution called "training" and "school"!
So, do you have the training to be able to make suitable files?
If yes, you shouldn't have make all these mistakes, so obviously either your training was not enough or not good enough, or you were a bad student (or you are a couldn't-care-less person)… then go back to (a better) school and pay more attention to what the teacher says.
If no, you must understand and accept that somebody has to do the job you didn't do, and this somebody has to be paid.
Besides, I am offended when I get fined unexpectedly".
You are not fined, you are charged fairly for the job that has to be done and that you were not able to do.
(but if you are a couldn't-care-less person, perhaps you deserve to be fined for your bad attitude?)
You also can do the maths: what is the cheapest? pay the printer to fix your files? or pay for a good training course? or pay a professionnal (competent) designer?