Replace Current eMail Program

We have 23 Users that currently use Zoho. Space is limited at 5GB, and we need way more space (50GB+) for a few accts but do not want to upgrade and spend lots of $$ per month. We have our own domain. We are looking for best affordable solution that works easily on all devices and desktops.
We will pay for setup & integration.

Please add e m Ai l to your bid or it will be considered spam, ignored and removed.