Hi Sam
Apologies, people here are just trying to help, and from what Laiba said in their original-post ("and received no text") it sounded-like a phone issue.
Here are some other things to consider:
• Check you're in a country where Microsoft Rewards is actually offered:
https://support.microsoft.com/en-gb/topic/microsoft-rewards-regions-9795ec47-c0f4-a33e-aede-738903359d63
• You can only use a phone-number on six different Microsoft accounts. If that applies, you must use a different phone-number, or log into a previous account and remove the number first
• VoIP phone-numbers (such as Skype) are not supported, only real mobile or landline numbers. Remember that some "eSIMs" can class as VoIP -- you'd have to confirm that with your network
• Your phone and computer must both be in the same-country as where the Microsoft Rewards points were earned when you try to link your number. If you're currently travelling, or are using a VPN, you won't be able to redeem them until you are back in the country where they were earned