The login name cannot be changed, so it sounds more like you're logging into the wrong account.

account name (the one you use to log in) cannot be changed.

The only way to contact Steam support is through: https://psteamhelp.yuanyoumao.com/en/

If someone contacts you through chat it's a scammer

steam support only talk inside their ticket system so what you did talk to was a scammer

--------------------------------------------------------------------------------------------------------------------
Your account was phished / hijacked. Follow steps 1- 8 to secure your account:

1. Scan for malware https://www.malwarebytes.com/

2. Check that the email and phone number on the Steam account are still yours.

3. Deauthorize all other devices https://psteamproxy.yuanyoumao.com/twofactor/manage

4. Change passwords from a trusted/clean device.

5. Generate new backup codes for your Mobile App https://psteamproxy.yuanyoumao.com/twofactor/manage

6. Revoke the API key https://psteamcommunity.yuanyoumao.com/dev/apikey (there should be nothing in the APIKEY)

7. Make sure your steam recovery email account is secure and still accessible.

8. Do a PW reset to recover any steam points spent in last 14 days.

Steam will NOT return lost funds or Items.

If any lost items are from a Trade Protected game, you might be able to recover them. See:
https://psteamhelp.yuanyoumao.com/en/faqs/view/365F-4BEE-2AE2-7BDD

------------------------------------------------------------------------------------------------------------------------

If you need help with Account Security or Recovery, please contact Steam Support.