Exhaust explosion

Friends, I gave the car polish, but I found the exhaust erupted. How much is the repair, how much does my average car peugeot 307 2005 model automatic

How well? Can you open up a little bit more?

It was completely normal when I gave the car. They took the car to the industry to fix their bio 1 day later, when I received it, there was an excessive noise from the exhaust, no problem at idle, a high noise when the gas pressed.

then these friends should not have wandered around the car, go and see what happened to this car?

it was already in my nerves. I gave the car 20km, 214000 km exhaust nothing exploded in their hands

Is it hard to do, how much is the average?

No, teacher, it is very likely that the exhaust is rubbed and drilled, it is not very logical to talk without seeing it.