Deleting products based on payment confirmation

[DeepaVaith]

Hi!
   I am splitting the cart so that each product has to be checked out individually and an order
will be created for each product.  This means that the user will go to Paypal to make a
payment as many times as there are items in the cart. 
   I would like to delete the items as soon as the payment is confirmed and email is sent out to
the buyer.  I am trying to do it by calling the removeproductcart function in helpers-cart.php
from the plgVmOnPaymentNotification()  in the Paypal.php file.  But this is not working at all
as noting happens, the items continue to sit in my cart.
   Please can you tell me where I should do this for the items to be removed?

Thanks,
Deepa