Question

“But don't send it to me through the mail
because the post office employees are a
bunch of crooks."
What made Lencho think that the post office
employees were a bunch of crooks?​

Answer 1

because he asked God for 100 pesos and didn't get the full amount he asked to God he thaugt post office employees took his some of the money.

Answer 2

The missing 30 pesos in the letter made lencho think that the post office employees had taken the missing pesos. So he thought they were a bunch of crooks.