An active or suspended subscription can be cancelled. Cancelled subscriptions cannot be reactivated. There is another pair of endpoints to suspend and reactivate subscriptions.

In order to cancel the subscription you must call the endpoint POST /api/v2/Payment/Subscriptions/{id}/cancel:

Request
POST /api/v2/Payment/Subscriptions/SUB_WNFRN9X2ZV8W3411BVM4D8UO6WJUOP/cancel HTTP/1.1
Host: connect-testing.secuconnect.com
Authorization: Bearer qb56tjj1bcvo9n2nj4u38k84lo
Content-Type: application/json
Accept: application/json
 
{
"reason": "Not satisfied with the service"
}

The field reason is optional.

If everthing is fine, the API responds with 200 OK, and the representation of the Subcription object:

Request
HTTP/1.1 200 OK
Content-Type: application/json
...
 
{
"object": "payment.subscriptions",
"id": "SUB_WNFRN9X2ZV8W3411BVM4D8UO6WJUOP",
"status": "cancelled",
"reason": "Not satisfied with the service"
}

The status canceled tells about the permanent deactivation.