The survey, released last month, is based on complaints filed with dozens of agencies across the country. The findings suggest that protecting yourself often depends on treating any solicitations skeptically, verifying information about major purchases and following up on any problems with the appropriate state agencies and consumer organizations. Despite widespread use of the do-not-call registry, consumers continue to receive unwanted and even fraudulent solicitations, the study found. Problems include the fact that fraudsters auto-dial from outside the United States and use prepaid cellphones that make tracing the calls very difficult, if not impossible. [Read: How to Avoid Online Ticket Scammers .] The most common complaints lodged in 2013 included car-related advertising or sales, home improvement or construction complaints, credit and debt-related disputes and false advertising. Disputes between landlords and tenants, utility problems and frauds such as fake lotteries or work-at-home schemes also made the top 10 list.