engine problem

hi, bought my first santa fe about 4 weeks ago. 2lt diesel, manual on a 2005 plate 66k on the clock.running really good and made up with it! However after booking it in to the main dealer to have the timing belt done things have deteriorated! Have only had the car back 4 days and have noticed when it starts there's a plume of smoke from exhaust which wasn't there prior also it wasn't starting as well. While out in it yesterday it lost power and clouds of smoke from exhaust, pulled into layby and engine clattering!! I have the feeling the timing belt hasn't been tensioned properly and jumped a tooth or two! Phoned garage but it was shut (Saturday afternoon) Breakdown truck to get it home. Has anyone had a similar problem and am i on the right trail of thought with the timing belt and what to do about it?? Thanks

 

Ask the dealer to take it back to the garage and correct the fault his workshop initiated ASAP. If he refuses tell him that you'll report him to Hyundai.