I need someone to adapt a contract for me.

there are a few text that should be adapted due to the change of rules.

its about gps live tracking services
normally we charge only for installation and client pays for the service monthly, and when he do not want the service anymore after a 1 year contract, they need to come to uninstall the device.

But now we are going change the rule. client should buy the device.
so client should pay for the device and installation.

this gps devices can be used by sms if someone do not want live tracking.
But if they want live tracking, we require them to sign a contract.

by signing the contract the client agrees that the devices will be locked by us, managed and connected to the server for live tracking of 1 year.
Client should pay a total of (example $120) in the year of contract. which means (example) $1 per month.
if payment is uncompleted, the device cannot be used by the client until he pays the rest full amount to keep using the device.

the existing contract is attached.
let me know your lowest price you can do it and how soon can you deliver the work.