in the uk its quite common for people to deliberately give the wrong species. I believe its because russians/horsefields don't need any paper work to be sold, where as some of the others species do.
This is Oliver, a fairly new addition that was dumped on us. as his previous owner got bored with the 3 she had. she sold 2 and this one was left in a tiny box with a hamster water bottle, dry cat food and no lights or heat. he's a little over 4 inch long and weighed 140gram when we got him...
I always use coir and never had any real problems. The only time it got in her eyes was when she had flipped and was trying to right her self she got some in one eye i just rinsed it out with tepid water and she was fine.
I'm in the uk an managed to find some mazuri on ebay. the seller was/is a member on here. sorry I can remember her name. I was told nutrazu was the same stuff just under a different name for the eu market, whether its true or not I'm not sure but it might be worth looking for it under that name...