Ibiza 6J TDI no longer starts

Hello my Ibiza TDI 6J Bj 2013 with 66 KW and only 98000 KM does not start. 2 workshops are in despair. It started with a defective line to the injector which has burst and the injector was loose. So new line and 2 new injectors. But it does not start. Now high pressure pump and pressure sensors waved. Again nothing. Then diesel filter and fuel pump changed. Same result. According to the workshop the pressure does not get out of the pump. Then again pump out other car changed – same result. My pump ran impeccable in another car. With start-up aid the engine starts immediately. Now the workshop wants to change the engine control unit. I stopped this now because I can’t imagine that and the costs are too high. Does anyone have a good idea ? car ran impeccable before.