Breach of Software Development Agreement: Can the Client Claim Refund and Damages for Delayed and Defective Delivery?

I entered into a written software development agreement with a software company in Pakistan for the development of a customized healthcare management system. The agreed project value was PKR 2,400,000, payable in installments against different development milestones. The agreement specified that the complete software would be delivered within six months and would include features such as patient management, appointment scheduling, billing, user authentication, reporting, and role-based access. I paid the initial installments as agreed. However, the developer failed to complete several important features within the agreed timeline. The software that was eventually provided contained significant defects, including problems with user authentication, appointment scheduling, database functionality, and reporting. Several of the agreed features were either incomplete or not functional. I repeatedly informed the developer about these problems and requested that they be corrected. Despite being given additional time, the developer failed to bring the software into conformity with the agreed specifications. The developer has now demanded the remaining payment, arguing that most of the work has been completed. The agreement contains clauses relating to acceptance of deliverables, correction of defects, intellectual property, termination, and dispute resolution, but it does not clearly state the exact amount of compensation payable in case of delay or defective performance. Under Pakistani law, does the developer's failure to deliver the agreed software within the specified time constitute a breach of contract? Can the client refuse to pay the remaining amount where substantial parts of the agreed deliverables are incomplete or defective? Can the client terminate the agreement and claim a refund of amounts already paid? What damages or other remedies may be available to the client for the developer's breach? How would a Pakistani court determine whether the defects are sufficiently serious to justify termination? What evidence should the client preserve to establish the developer's breach, such as the agreement, payment records, emails, messages, project specifications, and screenshots of defects? If the agreement contains a dispute-resolution or jurisdiction clause, how would that affect the client's ability to bring a claim before a Pakistani court? I would appreciate an explanation based specifically on Pakistani contract law, including the relevant statutory provisions and principles applicable to breach of contract and damages.