Anyone who has a credit card has probably already heard this advice: Make sure you scrutinize each bill you get. A new report serves as a good reminder that consumers must be extra vigilant about doing a line-by-line check of the bill. According to this new report, people in Wisconsin file more complaints about Capital One than any other credit card company. Citibank and Bank of America rounded out the top three credit card companies with complaints.

All told, Capital One had 5,200 complaints against it by residents of the state. The study, which was done by WISPIRG in Madison, showed that consumers complained most often about billing disputes. A representative of WISPIRG says federal officials have been doing more to help consumers since the creation of the Consumer Financial Protection Bureau. He says the CFPB has recovered around $800 million in refunds for consumers.