I hate that you lost your base but if it is any consolation, all your materials are still there so you lose only the time and aggravation to reassemble it, and you won't make this mistake again (having your spawn too close to the arena).
If you can get somewhere and hide and break aggro, they should go home to their arena, not camp your spawn. But you need to get them off you to do that, which means running a good distance and going into stealth, or entering a cave, or the like.