"Text Message from outpatients"

I have just received a terse text message , without knowing who it was addressed to, saying someone(?) is expected at Outpatients on Monday, none attendance will cost£120 to the hospital , and will lead to someone (?) being discharged to GP.

As neither I nor my husband have had an appointment letter we don't know what it is for. Texting on a Saturday evening when outpatients is closed is not helpful. I have never missed an appointment , but this terse email is dreadful