If your email and password are changed on the account then there is no way to recover the account. This company has a very strict policy with recovering accounts and if anything is different then you cannot recover the account. You must have the original email or phone number on the account.
The issue and preferred resolution, in GetHuman815429's own words:
So basically I went on steam workshop for csgo and it said free skins I clicked on the website and logged in and then I got a few emails saying email has changed and the mobile authentication has been Removed
I trust that Steam Software will make this right and come up with a resolution that is fair.
Help with my Steam Software issue
Follow this to see how it gets fixed
Find similar issues & what fixed it
Follow 3 or more issues like yours to increase the chances that another customer helps you find the right answer.