You can try to negotiate the base to 4+k, but you have no leverage and nothing to back yourself up. If you have a counter offer for more than 3.3k, this is where you tell them you're gonna take up the counter offer.
If you don't have anything, you can try your luck with a "if you offer 4k, I'll sign now". But if they call your bluff, you're back to square one at 3.3k.
They're low balling you, but they also know you don't have a backup.