DOFD is for credit reporting purposes. What's considered legally the start of SOL is often within a month or two of DOFD, but can vary widely. It could be the original SOL had yet to run out at the time they filed suit...
For example, if last payment was made May-1st due May 15th, then start of SOL would likely be Jun-15th at earliest when the next payment would have been due. Date of default isn't necessarily when last payment was, but when the account became past-due. Also, there's the issue of purchase activity. Some SOL statutes take that into account while others don't. And the judge may have some discretion on interpretation of SOL, so if it's close, ruling could go either way.
When exactly was the last payment and last purchase made back in or around May-2012? Something to research before even considering the effect of the subsequent Aug-2012 payment, which despite being below minimum to bring the account current, likely reaffirmed the debt nevertheless; resetting start of SOL.
Regardless, you could respond to the suit with an affirmative defense of the debt being "time barred". It might work out with the plaintiff withdrawing or the judge ruling in your favor. However, the odds aren't favorable given the information you've provided.
Another option, if you're able, is contacting the CA and settle the debt for a lumpsum payment before it goes to court. Settling now will avoid a judgement, which could stay on your credit reports for ~7 years, and cause difficulty in getting credit cards, loans, mortgage, etc.
