How to choose a small CRM system for a small business?

Question

PHP

Hello!
Requires a CRM system with a trace. requirements:
1. Users can be: a company employee, a client and an administrator
2. An employee can register clients, and an administrator registers an employee
3. Differentiation of access rights: an employee has access only to those clients for which he is assigned by the administrator or which he has registered; the client has access only to projects that are his
4. Registration takes place next. way: the client's mail and his full name are entered. Accesses to the panel are sent to this address, the same for the employee.
5. The customer and employees can comment on the project. Also change its status. (Approved, in progress, etc.)
6. Notifications about the change in the state of the project by mail to all users associated with it.
The question is this: is there a ready-made solution, albeit a paid one? If there is, then it should be possible to easily customize it for us (change statuses, fields, etc.)
If not, then advise a CMS on which it will be easy to implement
. many_to_many, because I started writing in codeigniter, and there is no such possibility. I would like that everything was to the maximum under the hood, as in rails.
Thank you!

Answer 1

Look towards OTRS

Answer 2

basecamp.com has it all.