Paypoint recently made a change to their callback system which means that a duplicate callback is made in the event that the original did not receive an HTTP response code of 200. In some cases, callbacks were triggering a redirect, meaning that a duplicate callback was triggered and excess income records were being added in nBill. I have updated the gateway so that it now always returns a 200 response code and additionally included a check to ensure that a callback has not already been processed. The updated gateway extension can be downloaded here:
http://www.nbill.co.uk/component/option,com_docman/Itemid,10/task,doc_details/gid,73/
