Hello,
I have read through your project description, and attachment, and am confident I can deliver your requirements.
I have spent the last 12 years consulting for and working with the UK's top telecom operators, and have developed several solutions like the one you require. I have dealt with several systems over the years, including 3CX, Asterisk, FreeSWITCH and YATE. I have also both developed complete in-house CRMs with this functionality, and modified existing CRMs to add this functionality using PHP.
I look forward to discussing the project with you.
Best regards,
Adnan