Oh darn. Well maybe it will be become available someday where you are. I am thinking perhaps it is fairly new yet and just not that available. I only noticed it a couple of months ago and before that I just did without having any mayo at all.
If you do try making it and are not sensitive to corn you could use honey instead of the agave nectar and you could use xanthan gum instead of the guar gum. For me guar gum is hard to find in my area but a little natural market fairly nearby has it so when I ever get there I buy several little containers of it.
When I get a chance I am going to try the recipe I put above and fuss with it. I may need it some day. I already had plenty of glutenfree baking flops so what's a few mayo flops to me. I notice both these products use apple cider vinegar which I may use instead but they also each have something called pea protein in them and I don't know what that is.
I am sorry your attempts at trying to make your own have not turned out well. I hated putting a recipe here which I have not tried but since I also went for so long without mayo I figured it was worth a try as I sympathize about your not having any mayo.