I use the 2 step verification and I don't have access to my old phone number that MS account uses

If this is a personal Microsoft account, use the sign-in recovery flow:

1. On the sign-in page, select I don’t have any of these if the code is being sent only to the old phone number.
2. If the phone/email security info shown does not look familiar, first confirm the account address is correct, including the domain such as .com vs .co.uk and the exact account name spelling.
3. If the account is correct, use the Account recovery form: Account recovery form.
4. If possible, complete the recovery form from a device and location previously used to sign in, such as the usual home or office device/network.

If this is a work or school account:

1. At sign-in, select Sign in another way if another verification method was previously added.
2. If no other method is available, select I don't have any of these when offered, and follow the prompts to replace the security info.
3. If no alternate method was ever set up, contact the organization’s IT help desk or administrator for help signing in.

Important:

• Do not repeatedly request codes to the old number or alternate methods, because excessive requests can temporarily block code delivery.
• If changing security info, do not change all security info at the same time, because the account may be restricted for 30 days.
• VOIP numbers cannot be used to receive verification codes; use a mobile phone number.

References:

• Common problems with two-step verification for a work or school account
• Use a screen reader to set up and troubleshoot multifactor authentication
• Help with the Microsoft account recovery form