Problems with messenger accounts

Hello,

I have a problem with 2 messenger accounts which I use,
I created a messenger account before I made a Facebook account so they are independent of one another, (to switch between them I had to go to switch account on both of them)

Note: Both use the same email address and phone number

. Recently my account got stuck on my Facebook linked messenger and when I go to switch to my non Facebook linked messenger it asks me to put in my email/phone number along with my password, once I put these in it tells me I'm already logged into that account, if I try to use "forgot password" I put in my email(which is the same for both accounts) and then it allows me to change the password on the account im already on(my facebook linked account)

Basically I want to access my old account which uses the same email and phone number as my fb messenger but when i do "forgot password" it ignores my old account and lets me change only my Fb password

Any help is much appreciated, thanks!