Gears jumping

Hi we have a 2010 skoda yeti 2 litre diesel . We recently had brakes renewed and asked the local garage to take a look at the jerking of gears when you go through gears  1-3 and they took it out and test drove it with 2 different mechanics, now they said it was the dual mass flywheel and that some of the teeth may be broken and the clutch needed replacing so we begrudgingly paid £1000 to fix it now when we picked it up and drove home yes it was nice and quieter to drive but it hadn’t rectified the problem so I took it back and the owner said straight away I noticed it when I test drove it before you picked it up , as you can imagine I was gobsmacked and asked why they didn’t mention it so the reply was leave it with us and we will look at it then we get a call to say that a filter that has something to do with the 4x4 was filthy and had bits in it and it was 95% better and for us to take it and try it  to which we said why didn’t you find that fault before we had the clutch done to witch he said the clutch needed replacing anyway  but just take the car and  try it out .

now up to date it still  has the same problem jerking from 1st to 3rd gear can anybody give me an idea what this problem could be as we are angry about the whole situation and don’t know wether to take it back to the garage only for them to find something else wrong.