The best answer depends on many things. There is no one size fits all way to approach this situation. What may be the rigt answer for someone else may be completely wrong for you. Important details I this analysis wok be what your objective is, what the economics of the property are, what your personal finances and debts are, what your exposure is to a deficiency judgment, and other issues as well.
The only way to gain an understanding of what your options and risks are is to consult an attorney who is knowledgable in this area of law to analyze all the relevant factors and to assist you in developing a strategy that best fits your particular situation.
Please note that the above is not intended as legal advice, it is for educational purposes only. No attorney-client relationship is created or is intended to be created hereby. You should contact a local attorney to discuss and to obtain legal advice.
If you are summoned to appear in court as you state, you better appear or you could loose whatever rights you may have. That said, you really do not give enough information to know what the case is all about. I suggest you schedule an appointment with an attorney in your area to go over the paperwork and provide advise.