I had similar with my mum a few months bak.
It's been going on for years the constant messages and what are you doing,what are you having for tea etc etc.
If I didn't reply straight away she would then call and if I didn't answer she would call dh phone or dc phone.
I had to get stroppy with her in the end and tell her if I don't reply it's because I'm busy and it's not an emergency so shel have to wait.
A few months ago I had a really bad week with her and dad constantly demanding I go over after work etc as they needed me to do stuff for them etc and I lost my tag with them both.
Reminded them I work around 60 hours a week in my own business. I have a house and family to run and they are young enough to be fully capable of looking after and occupying themselves and to stop forcing themselves and demanding on me all the time.
When I left that day I told them I wouldn't be over for at least a week and I wouldn't be replying to any messages hnless they were urgent as i was so so pissed ofd with them for being so bloody selfish.
i did get one apology message from my mum that was v brief.
the next time i went ovwr my auntie was there so it was oerfevt timjng to tell her and explain in frony of them all that its not ok to behave like it.
since then its totally differenr.
i pop over when i want to not when they want me to and they dont badger me