Looking for advice on managing cash flow implications in a reseller model.

Hi, we are hoping to have a new revenue stream for our US entity where we work as a reseller effectively sitting between Company X, and a few hundred customers, whereby we keep a small % of each transaction. Many thousands of transactions will occur each night for the hundreds of customers. Company X will take payment from us each night, and we’ll then need to recover the funds from the hundreds of customers. Company X will take it directly from us using ACH Direct Debit, however should we use the same method to recover the funds from the hundreds of customers, I have seen that it will actually take anywhere between 3-7 days for the transactions to be processed. If we use someone like Stripe, it then takes an additional 2 days to payout the funds from Stripe to our main bank account. This could create a huge cash flow implications for us. Therefore, I’m trying to work out a better solution. One option is charging the customers credit cards, and whilst quicker, the sums involved could very quickly (hopefully, in a sense) max out their cards. Another option is to take a deposit, but as transactions increase over time, the deposit would need to keep increasing, which would be challenging to maintain. A further option is to have the customers ‘fund’ an account with us, and ideally built in a way for it to auto top-up when below a certain amount. However, the challenge with that final option is the ability to stop the transactions occurring if they fail to top-up. If anyone has any experience of anything similar, it would be really great to get some advice! Many thanks, and appreciate it.