The amount found in your BIR Tax Due Remittance Record, which you can get from your Submissions View, is your proof that your tax payment has been remitted to the BIR. Taxumo uses payment channels that are recognized by the BIR (AABs) as valid payment channels. You will see which payment channel was used by Taxumo in the record as well.
The other components of your total payment have different supporting documentation:
Gateway Fee: Provided by the gateway chosen, usually an email from the chosen gateway: Paypal or Dragonpay.