Can't add users to Zoho CRM

Can't add users to Zoho CRM

Hi

We are trying to add 2 users to our Zoho CRM Standard Account.  We get error message 'Not able to charge your card.  Please contact payments@zohocorp.com'.  We have tried that with no reply.  Our account is paid every month for 5 users with no problem.

Could you please advise urgently?

Kind regards

Andy Cheshire