Last week we got new slate hearth put in, the guy who did the work convinced us that even though there will be a height difference between the pellet stove vent pipe and pipe going through the wall there are plenty of solutions for it. So now after we put the stove back in, the clearance difference is less than an inch, we tried to force the pipe in but it is not going all the way in as before. Is there any solution to this problem ? I have attached a picture to show what we are dealing with, we sincerely appreciate any suggestions.