create a link between my accounting software and WHMCS

I am looking for someone to create a link between my accounting software and WHMCS. When the status of an invoice changes (paid, credited, created or other) this status must also be processed in the accounting software. It should be a module in which I can specify the API key myself. The API reference of my accounting program can be found here: https://developer.jortt.nl/#jortt-api. I have no idea what something like that should cost and how much time it will take. Feel free to make an offer. Sorry, newcomers. I'm looking for someone with some reviews already. Good communication is key!