Cancel subscription doesn't work

We are implementing application which has to support in-app subscription based 
billing. To keep subscriptions up to date in our backend system we do 
integration with Google Play Android Developer API REST services 
(https://developers.google.com/android-publisher/v1/). Get operation works 
perfect but we have an issue with cancel operation - it always returns http 500 
error code. We see some forum posts about the same issue and all of them has no 
answer. 

Request data
POST https://www.googleapis.com/androidpublisher/v1/applications/[valid package 
name]/subscriptions/[valid subscription name]/purchases/[valid purchase 
token]/cancel?access_token=[valid access token] HTTP/1.1
Content-Length: 0
Host: www.googleapis.com

Response data
HTTP/1.1 500 Internal Server Error
Content-Type: application/json; charset=UTF-8
Date: Wed, 20 Feb 2013 10:18:44 GMT
Expires: Wed, 20 Feb 2013 10:18:44 GMT
Cache-Control: private, max-age=0
X-Content-Type-Options: nosniff
X-Frame-Options: SAMEORIGIN
X-XSS-Protection: 1; mode=block
Server: GSE
Content-Length: 52

{
 "error": {
  "code": 500,
  "message": null
 }
}

NOTE: get operation with the same params works as expected and returns this 
response body
{
 "kind": "androidpublisher#subscriptionPurchase",
 "initiationTimestampMsec": "1361282410620",
 "validUntilTimestampMsec": "1361908810620",
 "autoRenewing": true
}

Original issue reported on code.google.com by anatolsa...@gmail.com on 20 Feb 2013 at 10:24

fredlala8 / marketbilling

Cancel subscription doesn't work #105