Transitioning from Kaizala

So we are a small company, 10 folks on Teams, and about 15 part time workers (high school kids) that we communicate with.  With Kaizala retiring in the next 45 days I need to find an easy solution to move forward.  We have previously used GroupME then 2 years ago transitioned to Kaizala because of the better collaboration with our part time workers.  We have several kaizala groups depending on role and location for the 25 people to communicate.  Most of the communication is what needs to be done on shift that day and then folks reply back with various responses.  I was looking at how you could add phone numbers to a Teams Chat, but don't really see the ability to add a phone number to an actual team or channel.

I am not really interested in a full cost license for my 15 part time folks because they only get announcements once or twice a day and don't really reply much.  I would like to stay within the Office 365 umbrella if possible.  Is there some kind of way to do this?