online shopping on Opencart- No Advance payment

Required opencart developer who is having experience on atleast 8-10 projects on opencart. we have developed our site on opencart and its 90% completed, there are few thing which needs to be added and modified. 1)SMS & Email validation through OTP for customer registration & forgot password(1) 2)Login & Forgot password New password Creation(1) 3)Seller Register page(2) 4)Automation for Bulk upload of products (as per attached)(1) 5)Product Image error in admin side (empty image)(2) 6)Search design (search product layout)(1) 7)Invoice design (bar code with GST)(2) 8)Order confirmation Emails to admin and seller(1) 9)Mobile & tabs layout not properly (1) 10)payment gateway(1) 11)product pages design(as per attachment)(1) 12)Image change in the product page as per the color option(2) change We are not going to provide you any plugins or extensions from our end , every thing should be done from developer end. Payment terms : 50% of the payment after completing of tasks which are marked as (1) Rest 50% of the payment of the rest of pending tasks with testing Please ready the complete requirement & bid your price, once the bid price is accepted later budget will not be increased,also dont say based on the requirement again our price is increased. we cant increase the budget once the bid price is accepted. Note : only people who are having experience in opencart with atleast 8-10 projects and seller module. Thanks & Regards sushanth v