Sounds like they're away @Lynn981 They could have got a taxi to the airport or train station... If they're neighbours you have little to do with, they're not going to tell you are they? I don't tell anyone when we're going away, as I don't want to advertise it to the world and his husband! We only tend to go away for 3-4 day trips these days, 5 days tops, so by the time people realise we're away, we're back! IYSWIM.
Went away for 5 days a few years ago, (before we lived where we live now,) and some nosey twat reported us to RSPCA for leaving our cats alone, not fed, and to fend for themselves etc.
She was wrong. We had a petsitter who came in twice a day, fed them, changed their water, and spent 20-30 minutes with them fussing over them, and paying them attention. Stupid woman who reported us had egg on her face, as when the RSPCA popped to see us the day we got back, the petsitter was there. (We were due late afternoon, and she was seeing them one last time a few hours before we were due back.)
RSPCA officer told the startled petsitter that they'd been informed that the cats had been left alone for 5 days. She said 'well, you have been given the wrong information! I am surprised whoever reported it hasn't seen me. I've been here loads of times in the past 4 or 5 days.' The RSPCA officer just apologised, said they would let the 'informant' know, and then he left.
I know who it was, because another neighbour told me.
tl;dr sorry! Hope they're OK. (Your neighbours.) Have you got any news OP?