I am having problems with receiving PayPal notifications

Hi, Just hoping someone can help me resolve a problem I am having receiving PayPal Instant Payment Notifications when an item has been sold and paid for through eBay. I have contacted eBay but their answer was pretty generic and did not help. I was receiving the IPN ok until about a week ago. I haven't changed my email address or any of the settings in the meantime so I am at a loss as to what I do next. Can anyone help Please.

Thanks

Qicklock.