how can i be in arrears if my kitchen is not done?

this store is harassing me for payment, knowing full well that the kitchen cupboards is not done yet, was put in end of Jan-2015, and until end Feb the panel was only put in, I am still waiting for the little cupboard to be put in, they slaundering my fathers good name MR CARELSE and he is a good customer from their store,i got calls from February month for payment, and they even have the audacity to threaten me that they will come take out the units cos it seems as if I don't have money to pay, begging afterwards to please make payment and they will see to I that it will be put in afterwards, they don't call to tell me this or that, and telling me that I can also call them because they don't have me as a customer only, they have a lot of work and also forgets, then 2 weeks ago she GINA call on a Saturday and wants to know all of the above again,and that's where the threaten story comes in, and she never called back yet, and I asked for a fully fitted kitchen not 1 empty wall and the rest units only, I gave them a drawing and the lady said its too much she will see what she can do, when the cupboards was put in the 1 wall was blank and they did not even let me know why, bad attitud