Black particles in wine

A few weeks ago I bought a boxed wine from a liquor store in Lyndhurst, Johannesburg to entertaining friends. I bought Robertson Merlot and Natural sweet red. we opened the natural sweet red and everything was \OK"and then left out the merlot as we had an early evening. on the monday of that weekend I decided to open the merlot. As I poured in my glass I sipped it it tasted so Vile! and when I decided to pour it out in the sink. there black particles in the wine coming out. I wish I could post a picture to show you guys but I just found it disgusting and unsafe lord knows what those things were"