pre-paid or pre-purchased customer accounts

Hello,
i'm looking for an ecommerce system that could manage customer pre-paid customers accounts
Customers buy "points" or "tickets" that are crediting their accounts
Points/Tickets are sold per diffrent size books.

All other products price are evaluated in points/tickets currency and when basket is approved, the system controls taht the customer has enough points/tickets on his accounts. If not customer can feed his account buying new tickts/points.

This has several advantages:
- customer does not have to pull his bank card out each time he buys something, No stress, more comfort to buy.
- cask from multiple source for the owner
- no risk for non payment
- much less bank transaction fees
- opportunity to give new customers welcome credits
...
Customers can credit their account with credit card or sending a check to your office (your administrator moves your customer's account), etc

I could not find any ecommerce soft that lets me setup such an activity.
Does it exist ?
Is such function planned ?
Could that be part of specific development ? Who could do ?
Thanks,
André

is there nothing to answer for such a question ? 
Nor no question to ask about looking such a function, explaining the expected function ?
Kind a surprised !
Andre

Hello, I believe no one has replied with a simple solution to your feature request, because it is just not something simple to implement. Changing the way opencart handles processing to allow for a "point/credit" system would require major change to the core of opencart.
Your best chance is to place your request in the Commercial / Development section and hopefully someone can accommodate these changes for you.