We requested phone number. We'd contact them with a bank account to put money into. Back in the day, people didn't even use CC; heck, they refused to transfer

We requested phone number. We'd contact them with a bank account to put money into. Back in the day, people didn't even use CC; heck, they refused to transfer via ATM because they thought the money could disappear, so they'd drive up to a cash deposit machine to make online transactions. These days, there are still people who insist on cash. But you can automate it with virtual account numbers. So you'd assign a virtual account number to a customer, which forwards the money to your actual account. But since that virtual account number is uniquely assigned to a customer, you can track that this specific customer paid.