Nope, nothing is wrong with it, sorry just had to head off to work and didn't have enough time to give you a proper response.
Honestly, this is one of the better sketches I've had done of this for someone who hasn't drawn this sort of material before. You did an excellent job with all of the fetish details and I really see little room for improvement as far as your style goes. Also the character designs are well done and resemble the characters in your style. The anatomy is also spot on, I was especially surprised the amount of detail in the hands. That is an area I usually see a lot of artists have issues with (and the feet). I really have no complaints how this drawing turned out and everything I have to say is positive.
On another note would you perhaps be interested in drawing a few more images of these characters just in a few different poses? Just let me know if you are if you didn't mind this material or working with me. Thank you for the hard work you put into my commission :)!