First time and confused already

I placed an order on 11-06-15 got a text saying my 'order is out on delivery today' on monday 15-06-15 but i never received it. Thursday 17-06-15 i called their call centre and they told me it was returned wich i dont know why, and the lady i spoke to on the phone said it's out to on delivery again. I dont know how one would know their order has arrived with no notification or call, i mean i have been at my place all the time and i don't understand how my order had to be returned and still haven't received it.