Let me state the obvious here, however is managing your email solution (consultant, ISP, web hosting provider) probably is not doing the best job for your company.
I am going to tell you some reasons why you have work email problems and in tell you how to fix it in two words.
1. The person in charge of your email does not know what is he/she doing.
2. You still using POP to get your email
3. Bad design and implementation ( this take us back to number 1)
4. You think you can do it yourself.
5. You are looking for a cheap but not the right email solution for the company.
6. Your Internet connection is not reliable.
The solution for all these problems is pretty simple move your email to Office365. This is hosted solution from Microsoft that will cost you around $6 dollars a month per user.
Now you maybe asking what about migrating all your email to Office365 what a pain in the neck would be. Well not really is you are willing to expend some money on a email migration tool like MigrationWiz.
I have used that tool many times and i only have praises. It saves time, money and headaches. The best thing that they have is the documentation.