API and other development and debugging for CS-Cart

I need a high quality, focused, efficient software person for who can quickly and properly build API interfaces to fulfilment partner apps, such as Control Port of James and James in the UK and ShippingEasy in the US (I have one that's working for the US but it needs either fixing or replacing), debug and upgrade existing interfaces and solidify my multi-store CS-Cart installation that is growing rapidly, currently with 7 stores, soon to be 8 and then 9 and... The currently installed QuickBooks interfaces need fixing and I no longer want to rely on the provider of those add-ons. I need someone who is switched on, works quickly and accurately and understands the bigger technical picture and can deal with the minutiae. I have employed such people in my historical IT businesses, so I know you are out there. You need to have English as a very strong language, possibly a native speaker. Finding someone who picks things up quickly and brings me working solutions just as quickly is critical, and you know if this is you. If it's not you, please don't reply. Please...