No communication

On December 1st at around half past 4 I went to bp south road to fill petrol in my car.as I asked the attendant to fill unleaded petrol which he mistakenly filled diesel in my car.I never start my car as I then called the manager notifying him about what has happened he then assisting to call his mechanic to pump the diesel out.his mechanic then came and pumped it out the wrong way and then forth damaging the cars fuel line and other mechanical parts.I then notified my own mechanic as the car did not want to start.I then asked the manager to compensate me for a tow truck and the mechanics chargers as it was not my fault but theirs.he refused to do so.I then asked to speak to the owner he then told me he is out of town and must come in the next day to speak to him.its all been an inconvenience to me as I needed to go to work the next day.I had to take off from work to sort this matter out.but when I went to them the owner was still not in.I had to pay the tow truck and mechanic to sort my car out and have it fixed.all at a unfortunate cost I have invoices for all.bp has damaged my car and dont wanna own up.what should I do.