Timing belts

Hello everyone, have a question to the experts here in the forum. We have a Trafic, a real cargo ash. As it is our first delivery van, we are of course not so well versed. Our local workshop has taken over the maintenance. We did not know (ash about our head) that after 120000 km you have to change the timing belt. The workshop has always checked diligently RENAULT – WARDING in the booklet, so we assumed that the Trafic was properly maintained rde. Unfortunately, the workshop never made a change of timing belt, so that it is torn shortly before the lease return with all the consequences that affect the engine. Now the workshop blames us for this, because we never ordered this change. Now our question: doesn’t the workshop actually have to ensure that the car is properly guided through the inspection, especially since the execution of the RENAULT – WARTUNG has always been nicely confirmed? To your answer we are curious and thank you in advance. Versoline