Mel's sister Danielle claimed earlier this year that Mel has not spoken to her or her family for some time now.
But it seemed the girls were prepared to put their differences behind them as they planned a reunion while the star was in London.
They sent messages to each other as they organised the meeting but it then seemed to fall through as Danielle wrote: 'Can't believe my sister has stood me up after 3 yrs of waiting for that call. I am devastated and again disappointed beyond belief!!!!!!'
However Mel did not want to talk about it in front of the world on her Twitter page and wrote: 'hey I think best we text not tweet family matters are personal, you have my email and both mobiles they are all on,see you la.
'please please please text me you have both my mobiles,not responding to twitter. Thanks love.'
Danielle then added: 'I have to tweet u as its all about public image 4 you.4 me it was allways about family,that's a wrap, Love you.'
It is not known what messages were then sent back and forward but Danielle wrote: 'MONEY????? U have never given me a penny and I would never take a penny off you and I have NEVER sold a story on you!!LOVE YOU.'
But Mel claims the message about money did not come from her.
She said: 'omg just been hacked,changing my account someone is messin with me and my family,my sister has never asked me for money,i love her to bits.
'I would never have a twitter argument.'
However Danielle did not seem to believe her and added: 'hahahahaha what a convenient HACKER I've cried a river…..'