If the perpetrator's credit card has been maliciously overdrawn to 300,000 yuan and refuses to return it, the relevant provisions of sentencing standards are: if the amount of credit card fraud is relatively large, he shall be sentenced to fixed-term imprisonment of not more than five years or criminal detention, and shall 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. Article 196 of the Criminal Law of People's Republic of China (PRC) commits credit card fraud under any of the following circumstances. If the amount is relatively large, it 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 particularly 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 his property shall be confiscated: (1) using a forged credit card or using a credit card fraudulently obtained with false identity documents; (2) Using an invalid credit card; (3) Fraudulent use of another person's credit card; (4) malicious overdraft.