Three option letter received without any reason

Hello,

Could someone help me to clarify why me and my wife have both received the same letter at same day at or house.
Basically, we live in Ireland for the last 6 1/2 years, we come as students and we stayed 3 years with student stamp and when it expired we have no stamp since.
Mine and wife immigration registered address is the not one that I am leaving now, just the pps number have been updated to this new address 4 years ago.
This morning we just received a 3 option letter from immigration saying that we have 15 days to choose one of options, 1- leave the state, 2- Stay and wait to be deported, 3- Make a letter saying why we should not be deported.
My question is, how they know we are both here at this address? We never make any application and nothing special happened since the visa get expired. Only my wife works with tax paying, if was the case they are tracking on pps number, only her should have received the letter, how they know that I am here too?
If anyone have received that letter too could you please tell me what you have done in that case.

never received such thing but in think you need some serious advice if you intend to stay

a lawyer might be you best shot .

Best of luck !

Yes thank you, I have a appointment with a Lawyer tomorrow, lets see what she says.