42k from O2 - price rises

Hi,
I am considering joining Lebara from O2, I came across an ad that stated that 42000 have joined Lebara from O2, but I am unsure if I should believe this. How did you get this data? Also, what time period was this? Was it the week afterwards or multiple months?
Thanks

I left o2 due to the price increases. Way to expensive my brother and mum etc and probably dad leave o2.
I was with o2 about 23 years but their price increases end all loyalty.

apea18 I'll need to check to see if I can find out where that number came from, do you have a link to the add in question?