I think the chasing down a business thing really depends on the situation. Yes, the client should make efforts to follow up with the business if they know that money is owed for services rendered, but there’s only so much follow up that is reasonable, especially if the amount owed is unclear.
If the amount to be paid was already communicated and there’s a mailing address or e-transfer information available, it could be reasonable just to pay.
If the exact amount owed is unclear, and it seems clear that an invoice should have been received, it’s reasonable for the client to follow up a couple of times to ask about it, but should they have to keep doing so indefinitely?
For example, we called a local independent HVAC technician to come out and tell us why our furnace wasn’t working. No website or physical address, just a phone number. Turned out to be a quick and easy user error issue, and we asked if he wanted to be paid by cheque before leaving. He said no, and confirmed my husband’s email address for billing.
We didn’t hear anything, so my husband attempted to contact the technician to ask how much was owed and heard nothing back.
A year later, the furnace started to act up again, and we called the same guy, again offering to pay for the previous service, but no bill was sent or amount owed communicated. He came out, and gave us an estimate to replace some pipes (he said the exact amount was TBD once he had completed the work but that it would be maximum $X amount). We agreed, he got his supplies, came back and did the work. We asked if he wanted to be paid immediately. Again, he said no and confirmed my husband’s email address for invoicing.
Again, we heard nothing back, with no response to the follow-up.
At this point, I don’t think it’s our responsibility to keep chasing. We’ve made multiple attempts to offer payment and to ask how much is owed, and either the guy is very generous or needs some help handling his billing (likely the latter). I feel guilty, but also feel that this technician needs to come to the table himself if he wants to be paid.
Not that any of this is relevant to the OP’s situation, but just something I think about when I hear about the client’s responsibility to follow up.