I'm gonna go out on a limb and guess that your base was Swellendam Inc., removed by the Xeno Alliance yesterday? It will probably go down in history as the only base the Xenos ever successfully siege.
If so, we thought carefully before removing it, and decided that because it was on the end of the main lane highway and given its affiliation that you were planning to export Liberty ore from it.
If indeed this was your base, next time make sure you have fuel for your shield generator. Our Xeno Heavy Carrier (*cough passenger liner*)made short of it and we wouldn't have had a hope if you had stored fuel there. And don't have more than 50 million or so on there maximum.
I'd suggest reading the Player Base Construction Guide thoroughly, you don't want to be making those sort of mistakes later on.