Product: Money transfer, virtual currency, or money service

Case statement Good afternoon on XX/XX/2020, I requested to make an international electronic transfer ( International Wire ) through Wells Fargo Bank ( I have a savings / debit account at said bank ) for a total sum of {$20000.00} US dollars to a bank account ( XXXX XXXX ) in XXXX on behalf of my brother. 
Once the request for the operation ( international Wire ) was processed with my bank details and those of my beneficiary, I requested a printed document specifying the Exchange Rate or monetary equivalence of the Dollar = XXXX XXXX to know how much I should receive my beneficiary in your bank account. To which the Advisor / account representative gave me a printed format with the amount in dollars ( XXXX ) and the fee for the operation charge ( XXXX dollars ) but the exchange rate only wrote it to me by hand ( XXXX dollar = XXXX XXXX XXXX  ) for which my beneficiary is supposed to receive a total in XXXX XXXX  of {$430000.00} for the total of {$20000.00} dollars. Failing that, my beneficiary received only {$390000.00} pesos, that is, I lost {$36000.00} pesos ( the loss in dollars at the exchange rate that the lady told me of XXXX XXXX XXXX  for each dollar would be : {$1600.00} dollars ). Something that seems excessive to me given that I also paid a fee of XXXX dollars for the service. 
I insisted that he provide me with this type of change printed and not handwritten by the Account Executive who attended me, but she told me that her system did not produce that report, to which I told her that earlier this year I accompanied a friend to carry out a similar operation for {$13000.00} dollars in another bank ( XXXX XXXX ) and they did give him a printed sheet ( I have a photo of said document ) specifying the amount in XXXX XXXX that the beneficiary would receive for that amount of dollars. And indeed, the beneficiary did receive that amount. Without any variation, respecting the exchange rate at the time the procedure was carried out. 
Situation that I expected to happen with my case in Wells Fargo. Unfortunately it was not like that. 

The transfer was reflected in my beneficiary 's account on Friday, XX/XX/XXXX, but since the amount did not match what he was supposed to have received ( and in what we tried to determine if it was my transfer ) Later days ( Tuesday XX/XX/XXXX ) I went to the branch again to try to clarify with the lady who attended me when making the transfer the reason why I had received such a lower amount and she only told me that at the time the Wire passed the guy The exchange rate had dropped ( to XXXX pesos for each dollar ) to which I told him that for that reason I had requested by printed document the amount that my beneficiary would receive. And she alone wrote it to me by hand ( Exchange rate XXXX pesos x XXXX dollars = {$430000.00} XXXX XXXX  ) And given that " logic '' that it had been because the exchange rate fell, I told him what would have happened otherwise. What would have happened if the Exchange rate would have risen? Soon the bank was going to deposit more money than the XXXX that it was supposed to receive, to which the lady told me that that would never happen. 
To which I said : that is to say that I can lose XXXX dollars for the operation but in case the exchange rate had increased and therefore the money that my beneficiary would receive then there they would adjust to the exchange rate set on the document, the one for {$21.00}? It does not make me fair at all, it is more I consider it an abuse. 

And I left the bank branch thanking the attention. 

For your attention, I am grateful.