I would rely on the more common usage of "debit" and "credit".
Given further examination, we can separate this into two different actions.
1. The company pays upfront
This is a debit transaction.
1.1 A payment made or owed.
‘a further debit of £21 had been received from the Locomotive Department’
2. The company then receives a balance on our platform.
That balance is a form of credit that they can spend towards things on your platform.
Notice that this is not "credit" in the sense that you provide services and the company only pays afterwards, like how it is used in "credit card".
It is more closely related to "store credit", i.e. a debt which is owed to you (not by you).
2.2 Entitlement to a set amount of a particular company's goods or services, typically paid for in advance of use.
‘she had £15 credit on her account’
You need to distinguish between the money (legal tender) that is transferred, and the balance (fictional representation of the money that was paid to you) that is shown on the account.
If you were building a free-to-play game, and a player would send you money in exchange for gems/gold/...; then you would have already made that distinction quite clear. But because you are expressing the fictional credit of the company's account in real world currency, you are wrongly assuming that they are the same thing.
Even if they are always of equal value, it is still important to be able to distinguish between the two, as they represent different things.
Just because these two concepts are related, and may be of equal value, that does not prove that they express the same thing. My house number is currently the same as my age, but that doesn't mean that they express the same value. Funnily enough, this is the third time in my life where my age equals my house number, yet there is no direct correlation between the two.
Therefore, it would be correct to say that the debit sent to you by your customer (company), extends credit to the account of that customer (company).
But that doesn't help me with finding a name for the combined system.
Good point. Let me answer your two questions more directly:
- Should I call this system "Prepayment Management System"? one of my colleague suggested "Credit Management System" and "Account Balance Management System"
Externally, towards the customer (company), I would refrain from giving this system a name. It is a feature of your framework, not a standalone product or concept.
I would simply refer to the user as having an "account balance", and provide the option to "add credit" (to their account).
Internally, for your personal work situation, I would be okay with using either "Credit Management System" or "Account Balance Management System". Both are adequately descriptive, it is clear what the intention of the system is.
- Should I call the balance "Prepaid Balance" or "Credit Balance"?
I would opt for "Account balance". It's more correct in the user's context. It seems the most correct to say that the user will add credit to their balance (which is logically bound to their account).