I had that problem, log in to your account and scroll to invoices there is an option to pay by card.Hey folks. We've recently taken out the Tiekom 300gb sim thanks to this forum. We provided our Starling Euro account details. Tiekom invoiced our bank, which was rejected as Starling Euro does not allow invoicing. Do you pay with SEPA debit or using the portal under 'my bills' on the account page? The card payment portal won't load for us. TIA.
Worked for me twice.