The nose unreliable store and service

I purchased a alarm system on the 28th November and it said allow 8-10 working days for delivery. I couldn’t get hold of them on the landline nor on email, tried numerous times and got about two response which wasn’t accurate at all. I finally received the delivery on the 23rd December, when I open the package to check it looked as if it had been open before and this was not what was advertised, it had half the amount of sensors as per the advert. I sent numerous emails again and got one response saying they will look into it and come back to me. To date I have had no response from them. This is by far the worst online experience and poorest service. It’s shocking how this business operates.