Seeking a Twilio Developer to Create Custom VOIP

We are looking for a Twilio developer to create a custom VOIP for us. Our company will be using this phone system for marketing purposes, for inbound calls and outbound calls.

Typically, we will be using between 400 to 2000 phone numbers per month. These phone numbers need to be Verizon numbers so we can create phone verified accounts with them. We will also integrate the VOIP with ---------- pending on the price, we have 2 ways we are interested in having this created:

A) to have a replica of ----------
B) a very simple version that has inbound calls (can be answered on the computer), call flows, menu, call forwarding, text messaging, etc.

Please tell us:
1. A ball park estimate to complete this job
2. How long this project will take
3. If you already have a pre-built system that you can provide us.