Hi magd,
Welcome to the Community!
Both of the answers you've been provided are correct. Your credits will be paid out to to you at the end of each billing period under the assumption that your bill is on an actual reading. If it is not, these credits will not be paid out to you nor will they be paid if your bill has been generated using meter readings provided by yourself.
To receive monthly bills based on actual readings, you may be interested in having your meter upgraded to a smart meter. You can find out more here!
Kind regards,
Jayden