I made a payment using PayPal but received an email saying payment was not successful.

Hi,

I made a payment using PayPal for the DoctoralSchool2016 account, email tom.withers@ntu.ac.uk

I've received an email saying the payment hasn't worked.  Please can this be checked?  I don't know why this would be.

I want to purchase a silver package for 1 more year.

Thanks

I did check your account and found that on Oct 12, 2017 you upgraded your account to silver and the payment was successful. 

It seems you earlier had paid your subscription payment though your credit card. Your old subscription was not auto-renewed successfully on Oct 11, 2017. You must have received email for failed payment of old subscription plan. Since you have already upgraded your account again to silver yearly plan, your account is in good shape currently.