Not doing their job

I went to Samsung in Bloemfontein at Loch Logan to get myself the Samsung Galaxy Tablet 10.5. The sales person told me the he needs bank statements, we then went to go fetch that and went back to the store. He got all our information and said he will input this into the system. I agreed on R399.00 per month that was the deal he gave me. This all happened between 15:00 - 16:00. I came back later at 17:30 to find out if everything was ok, because they tried to call me. He told me that he could not insert the info into the system because there was a new deal coming out. Well thats not my problem i want my stuff sorted out. This is very poor service before head office goes home they need to make sure they added all the new deals for the weekend. I am very disappointed.