Email not even working of css solutions

Numerous attempt i tried emailing this company emails on website comes back address not found receive sms's last attempts or they can give me discount after sending them an email explaining reasons or to help with an affordable repaying of a cellc acc how can you send an email to a company which the email is not working i cant take calls at work so emails is easy for me to communicate the website says *** and the email keeps returning back to me