crack in tooth!!!!

Just got back from the dentist where i have had two venears removed as my gums have been receeding and will be having a 3/4 crown instead (dont know why i cant have venears again) but when i looked in the morror i could see a very small crack in the tooth next to where the venear had been removed, so i pointed it out to my dentist and he jumped at me that he didnt do it and i said well it wasnt there befor

He replyed that it just happens with age and its really nothing - just a hairline!!!!

i asked him why my gums were bleeding just at the start of the crack and he said its just because my gums are sensitive!!!!

So angry right now - but what can i do - the crack has faded since getting home which makes me believe that it was a fresh crack!!!!!!!