If you want to prove to someone that you did indeed pay for services, the best thing to do is to produce a receipt for that transaction.  A Lufkin woman allegedly wanted to show police that she did pay for a meal, however, what she produced was definitely not a receipt.  

According to a Lufkin Police report, Paula Self, 43, was arrested after she ate a meal at Lufkin BBQ and then left without paying. When an officer questioned her about the incident, she told him she had paid for her meal and that she had a receipt. She then handed him a criminal trespass warning that she had been previously issued

In a separate incident in the police report,  A woman reported being scammed out of her rent money by a man who called, claiming she had received a federal grant for $9,200. He told her that she had to purchase iTunes gift cards and give him the numbers on them in order to receive the grant money. She initially spent $200 on the cards and after giving the numbers, she received an email stating she would owe the government an additional $600 in order to claim her money. She told the man all she had left was $100  - the last of her rent money to pay it with. He then offered to pay the $500 out of his own pocket so she bought the additional $100 worth of iTunes cards and gave him the numbers. After doing so, the man told her he was not allowed to pay the money out of his own pocket and she would have to pay it. She then realized she was being scammed and filed a report.