The trouble is Mark started by saying "I'll get your business to No1 on Google", obviously he can't unless it's a very niche business, he then backtracked slightly and said "I'll get you on to the first page" which is different to what he was originally selling. Even then it's not that hard depending on what you enter on a search engine. Enter car mechanics london and you'll never be there, be more specific "car mechanics, brixton high street" and you'll most likely hit the first page, enter "car mechanics, brixton high street, bmw, specialists and you'll be No1. So it's not hard to actually deliver your promise, but whether people will go down to that specific level when searching is debatable.