Spam text message won't delete

Hi. I have a message that was received with a TON of people on it. Normal spam. I deleted it and reported it as junk. Someone then replied on the chat and now I can't get the new one deleted. It shows delete, I press delete and it just stays there. Any ideas? I tried the settings>messages>and changed the keep to 30 days. It didn't work. I don't want to reset my phone if I don't have to.

Thanks!