Honda Timing belt tensioner breaking after getting timing belt replaced

Hello everyone thank you for reading this or helping.

I just replaced the timing belt on my 2005 Honda Accord V6 at 120000 miles. I had the work done at a dealership because I thought that was the smartest move. However 600 miles later the tensioner broke, breaking the new belt and trashing the valves. Now I have thousands of dollars worth of work on a car I just maintained. Honda says they never place tensioner a because they do not go bad.

Originally I was going to get the work done in my home town in CO at my fathers trusted mechanic while I was working out there for a few months. I waited till I got home to Iowa because it was cheaper at my local honda dealership. After this happened I called my dad’s mechanic. He was more expensive because they always change a tensioner when they do a timing belt replacement. Saying they have been burnt too many times by a breaking tensioner.

Honda says it is not their fault and I have to pay. I do not agree. If the car was 300000 miles old maybe. But it is only 120000.

Has anyone dealt with tensioner breakage soon after a timing belt change? How many mechanics change a tensioner when they change a timing belt?

Again thank you all I am very stressed about this. I saved my money just to be able to do the timing belt. Now things are far worse and I’m broke.