What system would you recommend for issuing smtp?

Question

SMTP

The essence of the task is simple: It is
necessary for users to rent smtp for payment.
We have equipment (servers) The

question is what system (panel) to install - the panel should :
- have an intuitively simple and understandable user account where he can get his smtp login and password
- monitor traffic passing through smtp - number of bounce reports ( block smtp), number of fbl reports (block smtp).
- it would be nice to be able to accept payments through your personal account

Answer 1

self-written

Answer 2

I know the following options used by companies that offer paid mailboxes - in fact, a hosting service, stripped down to mail, but with its own advanced "backend":

intuitively simple and understandable user's personal account where he can get his smtp login and password

First there was cPanel, but after they raised the prices, there was a migration to DirectAdmin. Both are options for hosting, they need to be configured to remove the "hosting features".

accept payment through personal account

WHCMS (but I think they are also raising prices), Blesta (continues to be used even by budget providers) and HostBill (I know companies that are switching to them from WHCMS).