Getting customer invoices using Financials Graph API

Question

We are making an integration between a SharePoint Business Application and Business Central. We are using using Financials Graph API. We are facing two issues/blockers

1. Getting invoices. We are trying to get invoices. We used this https://learn.microsoft.com/en-us/graph/api/resources/dynamics-customerpayment?view=graph-rest-beta trying in the Graph explorer. We can't get this to work
2. Getting "totalSalesExcludingTax" - https://learn.microsoft.com/en-us/graph/api/resources/dynamics-customer?view=graph-rest-beta when running it in the graph explorer these values are not returned. "balance": "decimal",
   "overdueAmount": "numeric",
   "totalSalesExcludingTax": "numeric", Please advice.