How to organize telephony at the enterprise?

Question

Asterisk

At the moment the situation is as follows. There are 6 sales managers, 2 purchasing managers.
We work in 1s Trade Management 10.3.
There are several city numbers that practically no one calls, except for people who are interested in the company and trying to find contacts.
The main communication between managers and clients takes place via mobile communications. Each manager has his own mobile phone with a working SIM card, and they "speak" on it.
In order to improve the quality of service, save money, we want to somehow put things in order. We bought a piece of iron My-PBX U100 from the heat.
Now it's up to the small, to think over everything and fulfill it. I think so, take one SIP number, make outgoing calls only through it, for one thing warn all managers that in a month another mobile phone will be taken away from them and let them quietly transfer clients to a new single number.
Problems
1) How to redirect calls to the responsible manager? ut 10.3 This is not able to implement CRM for a long time and not very convenient in our industry.
2) SIP account I plan to use Megafon Multiphone. What are your opinions on this? Is it stable? Will it disappear in a few years, because there are no normal docks for it. There is no such support. In general, it's scary.
Clouds like all sorts of Mangooffices, I don’t consider Octels, because it’s expensive. (I may not quite understand how the cost is calculated)

Answer 1

if you plan to move to a multiphone, then why bother people with a change of numbers? transfer your current mobile phones to a megaphone and activate the multiphone service. for the first time, enable the simultaneous operation of mobile phones and SIP and bring the new solution to a sane state. Then take away mobile phones from managers

Answer 2

The Single Short Number (FMC) can help you
habrahabr.ru/company/garstelecom/blog/127834
www.corp.mts.ru/resheniya_dlya_biznesa/effektivnye...
The big three have this option