Gender reveal - was told BOTH SEXES!?

ok so I paid for a private scan to find out my babies gender as I have a boy already and wanted to find out what I'm having again ( I was told BOY at 16 weeks 3 days in a private scan ) then I had my 20 week scan and I told her I'm having a boy and she said she couldn't tell me the gender so told me to come back in 2 weeks ... went there again and had the same woman she said she couldn't really see babies bits but from what she can see she is guessing I'm having a girl ...