@rdtechservice,Rafael, Phone may be locked or Black listed and may not be worth the trouble,especially if they did not pay their cell bill as they did not pay you rent. When an iPhone is added to the Blacklist (reported as lost, stolen or has pending contract payments) from a Mobile Network, immediately it informs all the other Mobile Networks in the same country. This means that your iPhone will be blacklisted throughout that country and you will not be able to use any of those carriers. Read the complete article at link below. Just in case you choose to go ahead, I will post links to guide showing screen assy. replacement and available part to purchase but even after screen replacement there could be other issue's needing repair/replacement. Maybe phone could be sold for parts also Ebay/amazon/etc..
iPhone 5s Display Assembly Replacement
iPhone 5s LCD Screen and Digitizer Full Assembly