Escort tournament 16V BJ 97, problems mt used car warranty

Hello! Ford Escort Tournament 16 V Ghia Automatik EZ: 01/97 KM: 95140 90 HP Gasoline Hello I have had an escort for 6 months (approx. 6000 km of driving power) (data see above). I bought it from an Opel dealer. From the beginning, the death of a cold engine and the “rescue” of the automatic was claimed. Div. Ignition settings were changed and the ignition cables changed. Nothing really succeeded. Before 150 KM the drive was broken (drive train). Lt. the workshop was a complete used automatic transmission replaced. Here the guarantee takes over 100% work and 60% material. After approx. 150 KM the car has stopped again. The turning roller (?) of the timing belt is broken. Timing belt is OK. But the Ventiele are bent etc. Hander estimates 1400 EUR repair. Now the problem. The used car warranty refuses to pay. Since the customer service (all in the checkbook) has not been made by the Ford workshop. Thus is not sure The master of the Opel workshop thinks that the parts look very good and have been exchanged with high security. How do I best proceed ? Thank you!