Asterisk PBX configuration & IP solution

We are looking for an Asterisk PBX and IP solution. Asterisk need to be configured to our requirement. Current details and numbers we have for this project requirement are 2000 users 4000 number with incoming (calls only) call volumes are est at 20 calls a minute, average length of call is 3.2minutes. PBX needs to Pick up all calls read the CLI and check preloaded contact list, we will need Alpha tag function/software for any numbers not on contacts list and displayed by the CLI. Following call handling, the calls needs to be output either to answer phone or IP Solution to end user. The User is identified by preloaded telephone number at the front PBX, and also by the IP extension/user. This needs to be an bespoke IP solution alternative to VoIP SIP. a) Already have VPS that PBX and IP solution will need to be loaded onto. b) I will also need a full usage manual/Instructions