Pomona College Sophomore Transfer

Hello, I’m a parent of a sophomore transfer to Pomona College and it seems like Pomona does not do a good job in assisting transfers, can someone please clarify this for me: transfers are not given priority over freshmen in class registration so how can one be expected to graduate in three years (our case) if they can’t get into their prerequisite class? Is it true that you have to complete your undergraduate in 4 years and are not allowed to extend your stay at Pomona if needed? How does one navigate this, to whom should this concern be voiced if the professor won’t allow the student to register for the class?

Please enlighten me and any help or suggestions is appreciated. Thank you very much.