thanks for your inquiry.
"Admin can adjust a customer's token/credit balance by adding tokens to - or removing tokens from - the customer account."
I would like to known, if we have an API, or we can change directly in the database, to make possible, a faster and automatic process, to decrase credits to the user.
Example:
An user buy 3 credits.After he call a service from us.To pay it, the best option could be, a file generated by the billing with user account like:
john 1 credits
After we run a process (automatic) which remove a credit from john account.This process will read that file generated by billing.
We do not have specific API provided for this feature you requested.
But you can use normal object orientated programming to create a new customer credit record.
You can also write the data into database table ps_customer_credit.