You've had a message to call SS, not a policeman trying to arrest you.
And tbh it's the children's rights they will be more concerned with. As far as I know they are under no obligation to tell you who has made a complaint, and when you speak to the person you need to get hold of, doubtless they will tell you the detail of the potential complaint.
I think it's a bit early to be fussing about your rights, tbh. And it will likely make them think you've got something to hide. You should be more concerned about why people think (potentially) your kids are in danger.
I recently had a note put through my door on the 16th of January from my local council asking me to ring them on a number left and the note said,
I visited your home this afternoon to discuss with you information regarding your children (names of children given on the note) and it said I would be grateful if you would ring me to re-arrange a visit.
Anyway I have no idea what it's about and my partner and me have rang up at least 12 times on the 17th of January to which we were constantly told lie after lie, the woman who put the note through the door was apparently in a meeting all day (even though she left a voicemail message with my partner stating she was in court in the morning but would be available in the afternoon) and when we rang up to speak to the manager we were constantly told she wasn't available and that she wasn't in today.. We knew she was because someone earlier on in the day had said she was busy and if they could take a contact number they'd get her to ring back! She never did..
So the day the letter was put through the door (the 16th of January) my partner rang the council on the number left and was asked if there had been any domestic violence incidents recently, which there hasn't and they were told this and that we'd like to know why someone wants to visit the house, only to be told the information on their computer screen wasn't very clear so they didn't really know what it was about, so I said what information isn't very clear, they wouldn't tell me that..
What are our rights with regards to this? I mean we will gladly co-operate with the council etc but we had one incident a long time ago now where my partner had an argument with his mum in our house (she accused him of assault) and the police got involved and social services stuck there oar in and decided to take our 2 children at the time and put them with my partners mother!! This all then went to a child protection conference and they ruled that social services acted completely irresponsibly and unprofessional and it all went in our favour, my partner was also was taken to court by his mother because of this! And was acquitted of what she accused him of.
Lastly they keep asking when myself or my partner rings up if we are ALL in, what rights do we have with regards to this as I'm reliably informed they can't speak to our children if we don't agree.