New User registration didn't complete and now it's not allowing to register again

New User registration didn't complete and now it's not allowing to register again

Hi,

We tried creating Zoho Mail account for one of our clients with the domain name - coupons4sure.com
We were unable to create account as it threw some error after sending mobile verification OTP and now when we are trying to creating account , it says domain is taken.

When we try account recovery options it says mobile is not verified and email is not created.

How we recover and proceed with this domain.

Appreciate your quick response.