Unable to release static IP address

Hi I have been trying to remove a static IP address from my lightsail account, this IP is not attached to an instance. There was previously a rdns record but this was deleted days ago. I still can't remove it and get the error below: ReleaseStaticIp[eu-west-2]

The specified Static IP address cannot be released from your account. A reverse DNS record may be associated with the Static IP address. To unlock the address, contact AWS Support.

InvalidAddress.Locked

I have contacted support who keep saying that the rdns record is removed, i'm being charged for an unattached static ip which i cannot remove.

How do i resolve this? the only option i seem to have is to terminate my aws account.