I need a comprehensive platform, similar to Cashify, that allows users to sell old devices, buy refurbished ones, and book repair services. The system should include: Customer Website & Mobile App (Android & iOS): - Sell old devices - Buy refurbished devices - Book repair services - Verify device condition and price - Schedule pickup and track orders Admin Panel: - User management - Order management - Pricing and inventory control Partner/Technician App Core Backend: - Robust pricing engine - Efficient logistics system Ideal Skills & Experience: - Experience in developing multi-platform apps - Strong backend development skills - Familiarity with admin panel functionalities - Knowledge in logistics and pricing engines Please provide samples of similar work.