check my code

I have a medical application built by an outsourced Indian company. The idea of the application is to allow doctors to communicate with patients through chatting and pay for the appointments via in-app purchase. It is technically two apps one for the doctor and one for the patient and it supports both android and IOS. I was promised to receive a live application in 2 months [login to view URL], it took them more than 14 months and the application still have some bugs and crashes so i couldn't go live. I have requested the codes from the developer, but i only received the front end codes and i would need to pay more for the back end codes. I need an experienced developer to test the front end codes for me for both applications over android and IOS, a full detailed technical and manual testing and answer me the following questions: 1- Can the application be fixed and maintained ? 2- In case I only use the front end code and hire a new company to rebuild the back end code, how many hours would they need to work to complete the application bugs free ? 3- In case I buy the back end code, how many hours would be needed to complete the application bugs free ? 4- recommendations for big established and competent software developer companies in India, the i can trust to finish the application and maintain it with reasonable pricing I wish to sign a nondisclosure agreement before sharing the codes