If you upgrade your cell phone and have a used phone to sell, the Better Business Bureau warns that one company in particular has racked up nearly 2,500 customer complaints. Laptop & Desktop Repair doing business as cashforiphones.com has earned an 'F' rating from the BBB for either not paying for phones sent to them or paying well below the promised amount.

Better Business Bureau files show cashforiphones.com has a pattern of complaints from consumers alleging the business offers a high quote online but pays less than 15 percent of the quote. Difficulty has been noted reaching cashforiphones.com by phone to resolve a complaint.

The BBB reminds you that most retailers have some sort of buy-back program. When you sell a used phone make sure all personal data has been wiped from the phone.