Well from your description that goes a bit beyond the crazy touch inputs which was rather common in the earlier days, but rather points to a faulty screen. Still the tips in the first post of that topic could help you, but most likely you’ll have to get your screen replaced (the post also describes what info you should include in your support request).
Does an answerphone say when they are back in office again? Usually sending a request and then calling is the best way to get a fast reply and solution.