Outlook contact groups

Hi,

We use a specific m365 account for email blasts...and have 10 contact groups withing that account (and not a distro from m365), each contact group has a limit of 1000 contacts (limitation from microsoft), so we have 10 such groups as we send out to about 9000 people total (and microsoft has a limit of sending 10,000 emails per day per account).

Issue is a lot of times we get undeliverables because people in the groups either no longer work there or whatever...so its tough to clean up.

Is there a better way to do this?

1. For the contact groups itself? I thought a out creating a distro in m365 but then I have to add the 900p contacts into our tenant which would be annoying

2. Sending the blasts (without a crm or something like constant contact)

3.managing the lists from undeliverables

undeliverables

undeliverable

Thanks all.