It depends on the specific situation. You voluntarily tie a relative card to your friend, which means that his expenses can be paid by you. So 550 yuan can only be an economic dispute between you two, not a fraud. What's more, it's only 550 yuan, so just ask him for it directly. No one will accept the accusation of fraud. If the other party is really a liar, it is cheating on the Internet. You can report fraud to the public security organ. Whether it constitutes a crime depends on the amount.

If it is stolen, it is suspected of theft. (Pay attention to the last paragraph of Article 196 of the Criminal Law.) A low amount can constitute theft.

If it is a forged credit card, or someone else's credit card is fraudulently used (such as finding someone else's credit card and using it), it is suspected of credit card fraud (fraudulently using a credit card, amounting to 5000 yuan, which constitutes a crime).

Article 196 of the Criminal Law Whoever commits credit card fraud under any of the following circumstances, if the amount is relatively large, shall be sentenced to fixed-term imprisonment of not more than five years or criminal detention, and shall also be fined not less than 20,000 yuan but not more than 200,000 yuan; If the amount is huge or there are other serious circumstances, he shall be sentenced to fixed-term imprisonment of not less than five years but not more than ten years, and shall also be fined not less than 50,000 yuan but not more than 500,000 yuan; If the amount is especially huge or there are other especially serious circumstances, he shall be sentenced to fixed-term imprisonment of not less than 10 years or life imprisonment, and shall also be fined not less than 50,000 yuan but not more than 500,000 yuan or confiscated property:

(a) using a forged credit card, or using a credit card fraudulently obtained with a false identity certificate;

(2) Using an invalid credit card;

(3) Fraudulent use of another person's credit card;

(4) malicious overdraft.

The term "malicious overdraft" as mentioned in the preceding paragraph refers to the behavior that the cardholder overdraws beyond the prescribed limit or time limit for the purpose of illegal possession, and refuses to return it after being urged by the issuing bank.

Whoever steals a credit card and uses it shall be convicted and punished in accordance with the provisions of Article 264 of this Law. According to Article 266 of the Criminal Law of People's Republic of China (PRC), the crime of fraud refers to the act of fabricating facts or concealing the truth for the purpose of illegal possession, and defrauding a large amount of public or private property. The object of the crime of fraud is not to defraud other illegal interests. Its goal should also exclude loans from financial institutions. Because this law has specifically stipulated the crime of loan fraud in article 193.

It is generally believed that the basic structure of this crime is: the actor commits fraud for the purpose of illegal possession → the victim has a wrong understanding → the victim disposes of the property based on the wrong understanding → the actor obtains the property → the victim suffers property losses.

Extended data

According to the Interpretation of the Supreme People's Court and the Supreme People's Procuratorate on Several Issues Concerning the Specific Application of Laws in Handling Criminal Cases of Fraud (implemented on April 8, 201/), if the amount of public and private property is more than 3,000 yuan and less than 10,000 yuan, more than 30,000 yuan and more than 100,000 yuan, and more than 500,000 yuan, it should be considered as "a large amount" and "a huge amount".