At the start of 2017 we deprecated the Payments API. On 02-07-2018 we will take the remaining endpoints offline. From this moment on it will no longer be available for use.
The Paymens API has been fully replaced by the Invoice API, for more information on this API please check:
Please upgrade to either the Invoice API, or stop use of the Payments API.
For your convenience a PHP SDK has been developed for the Invoice Endpoints.
This is available on GitHub: https://github.com/Vleks/bol-plaza-sdk