USELESS CUSTOMER SERVICE

On the 27 February 2015 I returned to Samsung 1 x S4 on *** 1 x S***7,1 x tablet the First S4 was just for a screen replacement under warranty and the second for a quote to repair the unit as it was damaged. I recieved a quote for R4320 for the one repair and the next day another for the exact same amount for the other. This made me very suspicious and I contacted them and was told by email by Rudolf that he apologized but the technician had by mistake got the paper work mixed up and all was good all I needed to replace was the sub pcb for R890 after much argument as I did not agree with this, the phone was in complete working order when I dropped it off but agreed to pay the money. I then get a call and a email back and forth but eventually they agree to fix the phone all free of charge 100% and it is ready for collection. I am about to travel through but decided to just check and low and behold if the phone is ready but nothing has been done!!! After many promises to call me back etc on the 7th April I AM STILL WAITING !!! HOW DOES SUCH A BIG MULTI NATIONAL COMPANY OPERATE WITH SUCH BAD SERVICE AND THE NUMBER *** IS ENGAGED OR JUST RINGS!!!!