New VAT number has not replaced old number

We previously de-registered and had to register again. I am trying to submit our first VAT return via MTD but keep getting the error that the new number is not the number that HMRC is expecting. WE have a new number It appears that inside my HMRC account the old (de-registered) number is associated with our account and the new one has not been updated. What can be done?

Hi.
If you want to use the same Business Tax Account to submit your returns against your new VAT number then you will need to delete the VAT service associated with the old deregistered number and then you can enrol again with the new VAT number.
Please follow the instructions below:
login to the Business Tax Account
Select Manage Account
select Remove a tax duty or scheme
follow the on screen instructions.
 

Thank you, I have removed the VAT service, but now when I go to add the new one and complete the date, postcode fields, it comes up with the old number and not the new one. How do I add the new VAT account. Thank you

Hello
Please call the helpline so that they can assist you 0300 200 3701.
Thankyou.