OIL Leak

June/July 2015 bought a BMW 125i, started noticing oil marks in garage and reported it to BMW Neville geiges who was the sales rep at the time, they then repaired some gearbox parts and apparently my power steering pump. since then i've sent the car back seven times for the same issue and it 3/4 months later now sitting with the same issue. i have set aside some of my lecture classes trying to sort out this mess and all i get is that they cannot identify any oil leakage, i've taken yet another pic this morning with two witnesses who identified the same, so i guess they indirectly advising me that i'm mad if i can see an oil leak because it seems as though they cannot identifying this leak. its either it's a major issue and they not willing to take the cost associated with it or that i'm a young 27 male who doesn't seem to be valued for his business. i am honestly sick and tired of running up and down for the very same issue costing me a fortune because not only do i have to fill up with juice when i'm given a courtesy car but my fuel gets used up and not replaced, seriously what type of dealership is this,and by the way calling this a dealership is a overstatement.Pathetic honestly