Is it legal to replace Yandex Direct and Google Adwords banners by a city provider?

Question

Google

Such a situation, my provider replaces direct and adsense blocks for all clients with admitad banners.
And I'm interested in the side of the legality of this. After all, I want to advertise in YAN, buy advertising for my company focused only on my city. And here it turns out that a very significant part (this provider probably covers more than 50% of the city by clients) of my ads simply will not be shown.
On the one hand, the client can install an adblock for himself, and the provider seems to be able to provide a service for blocking banners. But here everything is somehow ambiguous.
I didn’t look to see if there was a substitution of links in Ali, Bangud, etc. it is necessary to calculate by cookies, I think. But IMHO, if there is such a substitution, then this is pure fraud. After all, the advertiser is ready to pay for the brought customers, and here it turns out that he also pays for those customers who know about these stores and go to them for purchases, only here at the "entrance of the store" there was "Vasya face control" who takes a percentage at the exit from customers who bought something, but no one is firing Vasya yet.

Answer 1

Provider services are data transfer without distortion. See your contract. If it says it can, then it can.