Help removing a 2nd pixel from my website

[leonl305]

Hi, i have two pixels installed, i don't have access to the older pixel. it looks like its a custom event tag based on the event name on the pixel helper. I removed the facebook marketing app. I installed my new pixel through GTM so no pixel ids are on the theme code or on the settings section. i made sure to remove any other GTM code that isnt the one that i own and i'm not sure what else to do. I inspected the page on the front end and it shows that the old pixel code is installed, but when i go to the theme code, it doesn't show. I need help fixing this. It's messing with our data tracking.