I had one for a few years in an aggressive tank that had lots of extra food and waste for it to eat. I did a quick google search and found out they are apparently a lot harder to keep than I thought. Here is what they say about them on several sites. T
his voracious feeder will quickly clean your aquarium of detritus and then burrow into your substrate, starve, and eventually begin to decay. 
I'd suggest that if you don't have a very big dirty tank (which it sounds like yours is still new and therefore pretty clean) you may want to give or sell it to someone that has a better chance of keeping it alive. I've heard they can be fed some food at night if your tank isn't dirty enough, but you may not want to have to do that. If I were closer I'd take it for sure as my 180g is constantly in a state of dirty with a baby shark (baby sitting it till the owner gets a bigger tank) that makes quite a bit of waste. It is really too bad they sent it to you when it is well known that they quickly run out of food and die...