365 tenant blocked for delivery e-mails

Hi   Good Day ! 

Microsoft have blocked our tenant for 2 weeks due spam originating from the domain.   Still we cannot send any e-mails and the block is not removed inspite of us contacting microsoft and their engineer connecting to the tenant and checking the tenant for any connectors and updating the outbound delivery settings.   The engineer is not responding.  How can we contact microsoft as it is a small business and no mails can be delivered. 

Please can some guide or help.

Thank you 

M  Carvalho