Les Schwab Tire Center review: Recently put bigger tires on my 2004 gmc envoy, now my transmission is messed up! I no longer have 3rd or 4th gears!

I recently purchased 4 brand new tires at les schwab in spanaway, wa. Unannounced to me these are bigger tires, I noticed my vehicle wasn't shifting into 3rd or 4th gears, its a automatic. I took it back to les schwab and spoke with the manager sean, he acted like he had no idea what happened? Then I took it to the dealership, $175 later, they gave me a summary of my 3rd & 4th gears being shot, then gave me an estimated price of $4500! I am on ssi, I cannot afford this! My vehicle ran perfectly before les schwab put the tires on it! The gilcrest, gmc dealership, I took it to said "what did you expect, it's les schwab" they see this often! I paid $850 for new tires & an alignment! What am I supposed to do now? Now I have to go to a transmission shop, probably costing close to $3, 000! I should have went to another tire shop, I never thought this would have happened! I hope you're board will view this and please try & resolve it for me