receiving agent; collection agency
A business or service that receives payments or items on behalf of another party, such as a payment collection service or a proxy for receiving goods.
This company handles payment collection for mail-order sales.
Using a collection agency service saves you the trouble of confirming payments.
代行 means acting on behalf of another; 収納代行 specifically refers to acting as an agent for receiving or collecting something.
収納 means storing or receiving; 収納代行 is the service of doing this on behalf of someone else.
payment collection agency service; convenience store payment acceptance service
Compound of 収納 (receiving, storage) and 代行 (agency, acting on behalf of).