Not receiving new messages in group text after switching to iPhone 15 plus

I was in several different group texts on my old phone (Samsung Galaxy S21). I recently switched to the iPhone 15 Plus and I am not receiving new texts that are being sent from these prior group texts. I have contacted Verizon and gone through all the troubleshooting they offered with no success. I am able to send new texts/group texts just fine, it's just that new messages from the previous groups I was in from the Samsung are not coming through. I hope that makes sense and thanks in advance for your help!