Deco express selling stock that they don't have

I have never experience such a bad service at Decor Express Siyabuswa Plaza I bought PVC ceiling on the 17/10/18 and when I went to fetch it I did not get it as they said the stock is not there ,to date I haven't received the ceiling I have been promised to get it from last week they say tomorrow after tomorrow,and when I said let me get a refund they say I must wait for 7days,as for the so called branch manager ooooh I don't have the words to explain His behaviour which He is not even apologetic to.