Classic Car/parts Classified Ads Site

I need an existing website rebuilt. I need you to design and build a website for my small business. Looking for a experienced quality driven backend web developer well-versed in utilizing APIs, wordpress, php, css, and woocommerce. Started the website with a unprofessional developer on upwork whom left us paying the bill for incomplete work. We wanted the developer to use eBay's Api to allow us to present on our site ALL the available classic cars and parts listed for sell on eBay. Instead the developer used eBay's Api to just provide us a page of content on our website. The developer did complete code to allow users to post new listings on our site for cars and parts and to pay for it via woocommerce, however it works on our old wordpress theme but not our new wordpress theme. We also have a API from escrow.com that's available for ads posted by new users to allow a secure transaction process with that partner. Here's our current site under our old theme [login to view URL] We need to extend the capabilities of our current code to not only just grab one page of content from eBay using their api, but to have it grab ALL of eBay's classic car and parts listings. We need multiple requests that can be made to eBay to gather more results. For example, add pagination (page 1 of results, page 2 of results, etc) where each page does an additional API requests to pull more results. Filters should be added, for example a request for "classic Ford cars", and another request for "classic Cadillac cars" could be made. Having multiple pages of results is going to be standard as we get more clients.  We also need to make the search box perform an api call using the given search criteria. Currently The checkout, the integration of woocommerce, the onsite detailed results are all to our satisfaction. Depending on pricing, we would like to also explorer the option of adding [login to view URL] and [login to view URL] api's to show ALL of the classic cars and parts on those two sites as well. Maximizing the ebay api as explained above under this woodpress theme ([login to view URL]) would be our primary focus. We would like to continue the code started that allows the posting of customer ads on our site to be displayed first then the content from ebay after. We would like to use the new theme above to work with our old and your new code to have the ability to use forms that allow drop down boxes to specify year, make, model or keyword to search for cars and parts.  Thank you, Nat