Can I still retrieve my old yahoo messenger chats if I have my yahoo mail account?

No. You only had a limited time to retrieve your Yahoo Messenger chats until November of 2018. All of that has since been deleted.

You can no longer retrieve your messenger conversation archive. It could only be done until the end of 2018.

No. Yahoo Messenger was terminated on July 19, 2018. You had 3 months warning from Verizon. 

damn that really sucks. ive been trying and couldnt find anything :/