On a self-written site, it is necessary to finalize the software part

Good afternoon dear freelancers, irresponsible performers handed over the project with a lot of flaws and disappeared. You need one or a group of specialists in the field of website programming.
Tasks:
1. After a person has registered on the site, to access the functionality of the site it was necessary to pass verification, there is a form for filling, but after a person fills it out, data on its filling do not come to the "admin panel", respectively, it is not possible to confirm or reject verification by an admin.
2. Add, delete, edit news comments from users to posts.
3. Page with closed content, only for those who purchase a subscription, there is also removal, adding editing of the material.
4. Sending messages to users within the site with notification by mail.

How much will it cost?