Rank Glitch and Concurrent player playing with my account

Product: Apex Legends
Platform:PC
Please specify your platform model. PC
AMD or Nvidia Model Number Nvidia Geforce GTX 1660 SUPER
Enter RAM memory size in GB 16GB
What is your gamertag/PSN ID/EA Account name? [edit: email address removed]
Please provide your squad mates' gamertag/PSN ID/EA Account name if possible.
Are you using any software with an overlay? No
Which Legend were you playing (if applicable)? Gibraltar
Which Legends were your squad mates using (if applicable)?
Where did the issue occur? In the lobby (waiting area before the match)
Which part of the map or menu were you in? If you don't remember the exact name, please describe the area or what you were trying to do in the menu. i was logged out
What were you doing when the issue occurred? E.g. respawning a squad mate at a beacon, using an ability, a squad mate left the game. when i logged in the game
Did your squad mates also experience the issue? No
How many matches had you played in a row before the issue occurred? since season 7 late
When did this happen? (dd.mm.yy hh:mm) 10.12.20
How often does the bug occur? Often (50% - 99%)
How severe is your issue? Major impacts to gameplay
What happens when the bug occurs? I cant Ready up in game and my rank is boosted ridiculousy to predator
What should be happening instead? ANYTHING BUT THIS
Steps: How can we find the bug ourselves? no idea i will post pictures to show u what i mean

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So basically ever since late of Season 7, i seemed to be having issues when i log in my account and it seems that my account has been used to boost other players concurrently when im playing and sometimes my IGN at the TOP changes to another name and back and it flickers back and forth. Season 4-7 im at MOST plat rank and mostly GOLD ranks. suddenly when there was a rank split in season 7 i was Master when i did not even play much rank games with my friends( as if someone played my account when i was logged off) also now come season 8 im now PREDATOR!!?? its a good problem many may say but i cant queue rank with my friends anymore and the worst thing happened when i bought the full lunar new year package for the heirloom shards and i was contemplating on which heirloom to buy and logged off for a good 30mins before i logged back in only to see that the account automatically bought the Gibraltars Heirloom. can somebody help please?

My IGN is DCJ_Carlito but sometimes it changes to Big Name and its wierd when it changes i cant click Ready and its as if its glitched.Seems to have some issues linked to the club activities