According to relevant policies and regulations, door-to-door collection is legal as long as it is not a violent collection and it is from the informal sector. The bank's on-site collection of credit card debts is to protect the bank's basic rights and interests, but if it is other credit disputes (not malicious credit card defaults), the public security organs have no right to intervene. If the loan contract does not stipulate the payment of interest, it will be deemed that there is no interest.