Connect Apparel Magic (open API) and Quickbooks Online

We are currently using Apparel Magic “AM” which is one of the QBO apps. They have an existing API written but it is not working correctly and does not bring over all of the fields in QBO that we need. For starters, the “customer type” field is erased in QBO when the API is synched. AM absolutely refuses to look into this and has told me that it is a QB issue. They have told me that their API does not write to the Customer Type field at all. I disagree with them. I populate the field in Quickbooks and when the API synchs – it wipes out the customer type. I need one of the fields in Apparel Magic to populate the field in QBO. The Sales Rep field is also not mapped to QBO at all. Taking it a step further – it would be really really helpful to have script that assigns products from AM to different products in QBO so that I can have multiple sales and cogs accounts reported. Currently, ALL products on invoice line items will only go to one QBO product or GL Account. I would be able to come up with some code such as look at the first 4 characters in AM to assign them to certain products in QBO. For example: Item in AM starts with SS23 – Item is mapped to a QBO item SS23. I have attached the files that AM has sent me that are generated out of their API. I have access to the API if I upgrade AM to their next tier. It is worth it for me to upgrade if we can write a correct API. I also do not have a server where the API would live so would need help advice on that.