Engine damage 270cdi

Moin together, need your help. I now also have an engine damage after countless repairs. The piston from the fourth cylinder is torn in the middle and has caused corresponding traces on the block. Angry because this ATM has only nearly 80tKM on it and lies outside the warranty time. Unfortunately, I can not find a new or revised ATM and also no one who can work up my soon – engine code OM612.965. Engine of a C/E/M-Class Code OM612.961 or OM612.962 to use? If yes – what must be changed/changed? Thank you in advance for your contributions!