My apex account got hacked!

I play Apex on PS4 before. After cross-progression, I linked it to my Steam account. At first, there were no problems, and the link worked. Suddenly, today I wanted to play Apex on Steam, but I was asked to sign in turns out my account was unlinked from Steam (i assume). I checked my Apex account via Apex ID tracker, and the hacker had changed my ID. Please help me get my account back

I try to contact EA support, already got the case number, but I accidentally pressed to close the  live chat  support. I can prove all the details needed (purchase history etc). It's my account since the beginning. I played apex for almost 6 years.. 

Can anyone help me?  I'd really appreciate your help. Thank you..