Provisioning of SSH dropbear accounts

I need creation in Linux and implementation in Whmcs, of a system provisioning SSH dropbear accounts. Customer buys whmcs product, he is asked to insert username/pass, and that account in created for 30 days in Linux on an available port. There are 10 different ports selectable. And there are 10 different pre-built locked config files that work specifically on a port, each one on its port. Lets say we have 10 files named: Port1 Port2 ...... Port10 So systems see that Port3,Port6 and Port8 are still available, and it assigns for example Port3 to the customer. The customer gets Port3 file (a prebuilt by me file that specifically works on port number 3) and a reminder .txt of this username/pass chosen. (these credential will let his locked file Port3 work. Don't worry about this) Other features: 1 unique SSH access per port When a server is full, no more account can be created on it. So a new spot is created on another server in the chain. Speed limiting 35 mbps and 70 mbps. 4 chains of servers: Red1 chain of servers having ports capped at 35 mbps Red2 chain of servers having ports capped at 70 mbps. Blue1 chain of servers having ports capped at 35 mbps Blue2 chain of servers having ports capped at 70 mbps. At the end of the 30 days, that SSH account expires and he has to buy a brand new ssh access. He can renew and extend before the expiration. You will have shell access to code all servers. Delivery in 3-5 days