Payments on CamPlus under paypal and payment failure sent to Gmail

I have 3 cams and registered for Cam Plus on my phone, I keep getting emails to my gmail acc. that payment has failed and my PayPal shows the payments re successful. When I try change my cams to gmail acc. it says I have to re register the cams. Does that mean pushing the button on the back of the cams?
If I choose not to do that, how do I stop the payment failure notification to my gmail acc?