We use this email for business communication. Even for paid customer, this get blocked on regular basis. Are you even capable of handling a small business with few 100 customers queries and replies. 

info@zainabchottani.com is block  Unable to send message;Reason:550 5.4.6 Mail rate exceeded limit. I don't know what the limit is and where i can see how many emails did i send out. My sent items shows 20.