<3 revlon colour stay

So i tryed this foundation after everyone was talking about it on youtube and loved it so i thought id get myself some more on ebay came to £9.50 with posting which was the same as last time but i resived it yesterday and noticed it was quite a bit smaller than my last one so i dug out the old one and that was 35ml and this new one is 30ml does any one know why this is ?.... although i dont mind as i love the foundation i was a tad gutted i must say as one of the reasons i loved it was the amount you got please leave comments if any one knows why this is ? <3