Just wondering how many recipients we can include in one email and how many emails we can send per day from a single Zoho user account.

We have an urgent message we need to send out to our clients (about 5000 people) but when we use mass emailing clients (MailChimp, Constant Contact, Sendy) most of the emails end up in the spam box and aren't opened. This isn't marketing material, it's purely informational -- no pictures or fruity formatting. We just need to send a normal email to a lot of people. Is there any way to do this over one or two days?

I've seen some info on this dotted about the web but nothing definitive.

Thanks for your help,

Harry