Unpivot multile columns

Hello ITManuel 

for sure you have to integrate my query in yours, but you have also to replace my datasource with your existing query. I can not test your query, but i try to fix it.

let
Source = Excel.Workbook(File.Contents("C:\Users\Manuelm\Desktop\Project reporting\GPC\GPC -- Invoices and Payments.xlsx"), null, true),
GPCInvPayStatus_Table = Source{[Item="GPCInvPayStatus",Kind="Table"]}[Data],
#"Removed Columns" = Table.RemoveColumns(GPCInvPayStatus_Table,{".", "Fälligkeit", "Zahlung", "Fäl.", "Zahl.Art", "Zahlungsart"})


ProjectColumns = List.Select(Table.ColumnNames(#"Removed Columns"), each not Text.Contains(_, "amount")),
AmountColumns = List.Select(Table.ColumnNames(#"Removed Columns"), each Text.Contains(_, "amount")),
GetProjectColumns = List.Combine(List.Transform(ProjectColumns, each Table.Column(#"Removed Columns", _))),
GetAmountColumns = List.Combine(List.Transform(AmountColumns, each Table.Column(#"Removed Columns", _))),
CreateFinalTable = Table.FromColumns({GetProjectColumns,GetAmountColumns }, {"Project", "Project amount"})

in
CreateFinalTable

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Have fun

Jimmy