imessage group texts, RCS, and SMS

hi all, i just got an android after having an iphone my whole life. wanted a change of pace as i'm so bored with iphone. im having an issue with texts, specifically group texts.

my phone number was moved from iphone to android and imessage is turned off. my coworkers and i have a group chat and we all had iphones until i switched. i started a new group chat, and im not getting a single one of their messages. on the flip side, people are texting me and it's still going through as imessage (until they manually send it as a text message). i wont get the text messages if they're sent as imessages.

what can i do to fix this? im missing important info frm my job because of this and i cannot keep having this happen. any advice would suffice. this learning curve is hard but this is definitely the most frustrating feat. thank you in advance!