Need a payment automation engine built Pax8 to Xero

We are seeking a proficient developer to create a payment automation engine that integrates Pax8 with Xero. This system will extract client license quantities and recommended retail prices from Microsoft and Dropsuite, subsequently generating invoices in Xero on the 1st of each month.

The solution will reside on our Linux server. Additionally, a user-friendly web interface is required for mapping Pax8 client names to their corresponding Xero counterparts. Invoices must include comprehensive details and adhere to standard 7-day payment terms.

Furthermore, a robust error-checking mechanism should be implemented to notify us via email in case of any discrepancies.