I accidentally deleted a group message and I can’t re-enter?

I accidentally deleted a group message I use almost every day (with about 15 other people in the gm) and I couldn’t find the gm to text after accidentally deleting it. I had my friend remove me and re add me to the gm, saying it looks like I’m in it like normal but when I get texts and try to reply, it’s not iMessage and members of the gm says I’m sending a text to a separate gm. What can I do?