MTS, I'm not familiar with that acronym, but if it's a shrimp or snail species, I suppose it is possible they are consuming the eggs...that's what they do. You may want to try moving the adults to a small temporary breeding enclosure to lay eggs if you have the means.
I'd also suggest bumping up the amount of java moss in the tank. If you send me a private message I might be able to help you with that...would only charge you shipping & packaging costs and it shouldn't be more than $10. I could throw in some hornwort as well. Plus, there'd be duckweed, which some people consider a pest species, but it's a great plant for breeding tanks as it gives fry lots of additional hiding spots as well as the micro-organisms that they feed on.
Also, I'm not sure how knowledgeable you are so please don't take offense, but are you certain you have a male and female pair? Females are uniformly grey with some speckling of red/chocolate spots where as males are very colorful with red, blue and yellow coloration.
Either way, I say give it some time. I've had two different gardneri varieties and generally they are all very productive species in terms of making babies. If you don't see fry within a month or two, there's definitely something that needs to be addressed, but I'm not sure what that would be.
Your pH sounds fine and the temp thing isn't all that important...just keep in mind that warmer temps will help increase breeding.
As far as the pic goes, it's a tad blurry, and since the plant is so small, that makes it all the more difficult to positively identify. Probably not a lot you can do about that unless you have a higher end camera with macro. But, for what it's worth, throw my vote in as your plant being a small crypt.
