Worst part... It is STILL with them!!!!!

I am so ****ed off with the technicians at Samsung Gateway. I took in my tab4 7' n they told me they could fix it because it is within warranty, I must bring my proof. I brought it back on the 9th of December, on the 5th of Jan I called n they said they would call back- they didn't. I left work n went there, they tell me the phone is not fixed because it has scratches!! Question: did it not have scratches when it came in? It did. Why did you wait almost a month to tell me this?! Why did you not send me packing day 1?! Has company policy changed since then? No. How do I know that nothing funny has been done to it in these three weeks?? I am no IT specialist, so I wouldn't know. I spoke to their Manager in Springfield Sagree today n she says tells me that they are professionals. Is this how professionals behave?! According to my knowledge, if the error was on your part you carry the liability and RECTIFY the mistake. Is it because I am that worthless a customer that they treat me in such a manner? In fact, I am not alone because a few friends have also complained about these Samsung service centres. I have been calm about this but now I am NOT happy! Worst part: it is STILL with them