@Sive Good morning, when you made the payment was it over the phone or via My3? When you are contacting Customer Care what number are you calling? You should be able to get through to our payments team.
On the other hand, making a payment on the 8th covers any bills due to that point of time. I'm wondering did you receive another bill shortly after with a new balance for a different billing cycle date? For example, you paid €45 on the 8th of December and that covered your November 18th bill, then the next bill arrived on the 18th of December for the same amount and this covers a different period of time.
