lost my gmail and now 3 ppl use it to play on my acc

I could like to get help since the gmail that my acc is logged on is an gmail i used on my old phone and forgot to log in that gmail when i changed my mobile phone and now when i came back to play the game a few days ago i noticed that i had 0 friends and only 2 arabs and my user name changed and i went in the settings to look and saw that a Reeder phone and Xiaomi phone had been logging evry day on my acc through the mail which i really want to unlink it beacuse i dont want them to be able to log in anymore as im using facebook to log in the acc right now but im concerned that they might unlink my facebook faster than il unlink the gmail and i had tried to do it with the costumer service but its got declined and i dont know what to do anymore and i really dont want to lose my acc since i play for 5 years i dont know if its will help but my UID is 5377899273 if something can be done il be very happy about it and also here are some pics i hope something can be done and no i dont have the phone number added which is very stupid of me for not putting it.