In order to validate your phone number, you have to enter your phone number on this page. Please make sure you enter it in the correct way.
If you have entered it and hit the verification button, you will receive an SMS / text message with a verification code. Enter this code on the corresponding page and your phone number will be validated.
If, however, you don't receive this code, then it's likely due to a delay or an error with the SMS sending service. Please wait up to 10 minutes while keeping the page open where you need to enter the code. It might help to completely switch off your phone and reboot it, to enforce it to reconnect to the mobile network.
If all this doesn't help, please contact us and we'll see how we can help you.