Ford dealer installing pirate parts and not taking responsibility

Bought brand new Ford Ranger 2.2 XL, all 3 services 20000km, 40000km and 60000km was done at ford Vereeniging, on 73000km I took it to Park Ford Vanderbijlpark due to the vehicle loosing power at 2500rpm and the spanner light comes on the speedo cluster after a while of driving it goes out of limp mode and the spanner light goes off, however the revs cant go above 2500rpm while driving, when the vehicle was inspected by Park Ford Vanderbijlpark to do fault finding they found that a pirate part fuel filter was installed, according to records this was done on 40000km. When Park Ford contacted Vereeniging Ford they claimed that they will never install a pirate part, however the service history was done by them, they installed the pirate part and dont want to take responsibility for it, and they definitely installed a pirate part no one else could have, the vehicle is still under warranty and service plan, why would I or anyone else install a pirate part and carry the cost thereof when its still under warranty and service plan, if anything is wrong with the vehicle then it needs to go to the dealer and their responsibility to repair or service at no cost to the customer. Park Ford tried contacting the Service Manager at Ford Vereeniging by the name of Maryke to no avail to get authorization that they will carry the cost of replacement. I in turn contacted Ford SA Customer care, they also tried contacting Maryke at Ford Vereeniging to no avail, and all other personel say theres nothing they can do. Ford SA opened a case number for this issue to be investigated, dealer not even getting back to Ford SA, awaiting feedback, issue still not resolved and vehicle not repaired