I'll second checking out Basecamp. We use both Slack and Basecamp. ZenDesk for customer issues. Everything tied together, both Slack and Basecamp have decent to

I'll second checking out Basecamp. We use both Slack and Basecamp. ZenDesk for customer issues. Everything tied together, both Slack and Basecamp have decent tools to integrate so you get alerts where you need them. Basecamp has a nice set of tools for projects and planning. I can't say I LOVE it (and I don't hate it), but I do love their support people. You could probably get away with just using Basecamp as well. We did for quite a long time.