Outlook cannot send Emails

We are using Outlook 365 and our email has been blocked. Error code is Remote server returned '550 5.7.705 Access denied, tenant has exceeded threshold.

 The problem we have is our domains are held at Ionos and we purchased office 365 through them. When we go into the admin part of 365 for support the only support option we are given is Ionos. 

Ionos say that we have to contact Microsoft to raise a ticket but when you call them it gives you a web link back to your admin screen.

 Is there another way of contacting Microsoft or can I contact another Microsoft seller and migrate away from Ionos? Then maybe be able to raise a ticket through my admin centre to Microsoft?

 We cannot send any emails?

TIA