Component not found calling onPaymnetNotificatiion

-- url of the page with the problem -- : localhost
-- HikaShop version -- : 2.3.4
-- Joomla version -- : 3.3.5
-- PHP version -- : 5.4.4
-- Browser(s) name and version -- : safari 7.0.6
-- Error-message(debug-mod must be tuned on) -- : ERROR: 404 - COMPONENT NOT FOUND

Hi, my problem is probably simple and having to do with my limited Joomla experience. I am trying to write a payment plugin for the {forte} payment gateway. My plugin takes me to my payment page and I can make the payment with {forte} but when I try to redirect to onPaymentNotification() I get a "404:Component Not Found" which surprises me since I have been using Hikashop for 6 weeks. Apparently, I am misunderstanding something. I am trying to call onPaymentNotification by posting to:

com.singledivers.com:8888/index.php?opti...component&lang=en-GB '

I have replaced this url with another in my code and it redirects correctly (as a test) but when I try to redirect here I get a "404:Component Not Found" error. What would cause a component not found error when the component appears to be there? Am I even trying to call thus function correctly?

I found the problem. It must be posted with type 'get' and the function I am using defaulted to 'post'. Redirecting as a GET works fine. Sorry for the inconvenience.