No answers on fault on brand new enjin on Ranger

Second hand Ranger, enjin damage. Replaced with brand new enjin which we paid cash, did less than 1000km and we were stranded again. Now I am told by dealer that no such technical issues have been encountered before, upon asking for next steps and proof of tests done I don't even receive feedback or answers. Who can pay thousands additional on a vehicle and wait patiently with no answers or remedy from June (vehicle broke down the first time in June).