Lost access via SSH and SFTP

Hi all, I'm hoping someone can help me!

I have just renewed certificates for my service, and was looking to SFTP these on to my EC2 instance. I am unable to connect via SFTP (using WINSCP) and I'm also unable to log on via SSH (using Putty) to my instance. Both were working previously, using my keys generated for the instance.

I had an issue with my payment method a while ago, and wondering if my account has possibly been set to Isolate (as have seen some other users with the same issues where that had been the problem!)

SSH log in results in the error "Network error: Connection timed out"
SFTP results in the error "Connection to <instance> timed out"