Reshape multi-header table in python

I am new to python and trying to reshape table from excel file as I have multiple header I am trying to convert first header into 2 separate column. i am attaching my code output and data here. Input Table

import pandas as pd
import numpy as nm

df = pd.read_excel(r'.\test.xlsx', header=[0, 1])
df = (df.stack(0, dropna=False)
        .rename_axis(index=('Customer','Date'), columns=None)
        .reset_index())
df.to_csv(r'.\testnew.csv',index=False)
print(df)

Printed Output -

Desired Output -