Item not satisfying. Customer in the dark

I bought a Pattex No More Nails tack/glue on 22nd Nov and hen I got home it didn't want to come out. I took it back for them to either check or replace. Isaac told me I didn't open it and he did that for me. Only to tell me later that I further needed to buy what they call a \gun"to push it out. The problem is that I wouldn't have bought it in the first place should I have known. There was no one to advise me if I knew what I was buying. They needed to make a sale. Now I'm stuck with it being the woman and also the \""man\"" of the house not knowing what next step to do. They should have boards that tell customers that whatever u buy u will also need to buy something else for u to use it successfully. So does it mean whenever u buy at Builders u should go to customer services to find out how to use and if the product is suitable for women or men? The answer is YES. Or avoid it by all means as there will be no one to assist with u with wat u buying and u will end up with something u can't use hence u paid for. Am so dissapointed and am not looking forward for the next sale at the shop"""