I understand Kanna. Well, I don't know what it's like about Loan agreement in Japan, but in my country, we can tell that every organizations that have "Debt collector" is an illegal one. They are 100% bad guys.
If you can't give money+interest back to the lender, you lose the things you use to guarantee the loan, for example, house, car, or land. Not get some debt collector guys knock your house's door.
I think the reason like "but she is a debt collector!" is more understandable than "but you are both girls!". They are dangerous people and IF there is a good one, it's still dangerous to get involved with them.