Hi Alison! We can’t give your definitive advice as we’re not Monzo employees (you can tell who is because they’ll have a :mondo: logo where we’ve got a coloured dot)… But, I regularly transfer money between accounts in my name and I’ve never had a problem.
Take a look at this thread which gives people’s opinions on where these reviews are coming from. The popular theories are that these are either fraudsters upset that their nefarious deeds have been noticed or that someone has been paid to create a negative impression of Monzo.
I haven’t been affected by this issue personally, and don’t have any inside information, so can’t claim any of these theories are true with any certainty. What I can say though is that there is a vibrant community here, over a million Monzo accounts, and no one that I know has ever known anyone to have a problem with Monzo - so read into that what you will!