How to Cancel a Pending Payment?

[eamorgana]

The question is simple - How to cancel a pending payment?
I accidently used my PayPal Mastercard number when I was paying a bill via my mobile phone.
So, now I need to cancel the payment that is showing in my PayPal account as PENDING

Thanks

[kernowlass]

@eamorgana 

You can't cancel a processing payment, if its pending it should time out a maximum of 30 days.