Let's say you are offering a package price for Service-A . It costs $10 which is equivalent to 10 credits. You provide the customer the flexibility to use the credits for other services you provide.
Credits can be exchanged for Service-B
Credits can be used for Service-B
Credits is redeemable for Service-B
Redeem: gain or regain possession of (something) in exchange for payment.
Exchange: give something and receive something of the same kind in return.
used: take or consume (an amount) from a limited supply
Do the above words aptly describe the situation? Before checking the dictionary, I assume either redeem or exchange should be easily understood. After checking the dictionary, I have second thoughts about them and I do not know which word to use. Is use a better choice? Is there a more appropriate word to fit the context?