TROUBLE WITH MY "ROUNDCUBE" EMAIL FOR MY WEBSITE............AGAIN!

Seems like I / WE are having issues with the email product (Roundcube) portion of my HOMESTEAD account yet AGAIN! Tried sending a reply to a business email 7 times and each time it was labeled "undeliverable". Having another email address (COMCAST) I replied through it and the first pass iot went through. HOW CAN YOU OPERATE A BUSINESS WITH THESE............INTERMITTENT (?) ISSUES TAKING PLACE ?? WHEN WILL HOMESTEAD ADDRESS THE ISSUE AND PROVIDE A BETTER PRODUCT UNLESS THEY CAN FIX THIS ONE (ROUNDCUBE EMAIL). Getting very frustrated and questioning how many opportunities I may have missed because my email account seems to have yet another case of the hick-ups ??? H E L P !!!!!! AND PLEASE FIX THE ISSUE ASAP..... OR MAYBE ITS TIME TO CONSIDER ANOTHER HOSTING COMPANY.