What is the best way to connect a virtual number?

Question

Telephony

The company currently has its own city mobile number.
Now the task is to connect telephony, but with minimal losses for ourselves and clients.
Telephony was chosen for free, but there are a number of nuances that I would like to know:
1) Zadarma offers to buy only a virtual landline number starting with +7391 9 , and we need +7391 2
2) so there is an option to connect a number from another provider. With Megafon and its multiphone, it was not possible to transfer while maintaining the city number, so you need to find the provider of the virtual number. Can you please tell me some good and trusted virtual number providers?
3) However, if you connect a virtual number, the old one is still lost, and you need to set up call forwarding, where incoming calls are charged as outgoing. Is there a way to make redirects free?
4) In principle, is there a way to painlessly survive a change of number for a company whose phone is the main way to communicate with customers?

Answer 1

one)

+73919, but we need +73912

if you try to terminate calls from a number in another city, then this is punishable, in some cases it is also very painful for the budget.
2) It makes sense to poke local providers with a stick.
3) There is no free forwarding.
4) Yes, there is an old number for half a year on which an answering machine hangs saying that the number is now such and such, after which it is redirected to a new number, just take care that there is a correct number in absolutely all advertising and in all Internet services (2gis \ google maps, etc. .d.). Other options in the form of "but for now we will temporarily make a full call forwarding without notifying that the number will not be available soon" will eventually result in 2 numbers.