Hey there,
I understand that when the stock hits 0, the script doesn't invoice and capture the funds. I can certainly solve this problem in a short period of time, while keeping the cost as low as possible. I've vast experience with Magento (have worked with almost 150+ projects) so I'm 100% confident in working on this problem.
If you have any questions or concerns, we can schedule a call, what date and time best works for you?
Sincerely,
Wasif