A scammed extension

Hi,
I would like to report a scammed extension:WP Symposium Pro
I paid 50 dollars to buy this extension in last year, it only give 7 days for refund claim, he told me that his extension will be able to do everything for my site, after installing it, I find that it is not good and asked him questions, he answered me other things to lose money time, on the 5th day, I asked him for the refund, he tried to hang around and 7 days passed, he refused me the refund it triggered the recurring payment on Paypal and having debited another 100 dollars to this year, now he refused to refund me the 100 dollars, I do not know how to contact the person in charge of WordPress so that he stops the collaboration with this scammed company.
I hope people, especially not buy the extension from this company.