"Response Rate" doesn't work!

Sometimes I answer to a message but must answer a second time for the system to register it, at least regarding the response rate, also don't know if the costumer received my message. I always check my response rate after responding and this happens. Maybe this is not the case of this topic though.

Hi there,

Are you sure you don't have any unanswered messages? Our system shows there's a message from 2 months ago that you haven't read.