Order placed and paid in full, but not delivered

I've placed an order for lights, sensors and trunking on 8/2/2016, and paid it in full as well. They told me delivery usually takes 3 - 5 working days, but up until today I have not received my order. Everytime I contact them, they give me a new excuse, or they say the shipped the order yesterday, then a few days later then they tell me again that they've shipped the order \yesterday\" again. This is starting to become ridiculous and they are very unproffesional"