The new Macbook Air 2018 keyboard is unusable

Within two days of buying my Macbook Air 2018, the keyboard was defective. My E, R, T, keys would either sputter, with double or triplet repeats, or it would not type at all— e.g. typing the mere word "the" would take 3 or 4 tries, and would result in "ttthe".

I brought my Macbook in for service but to my horror, none of the Macbook Stores had any replacement keys. Genius bar told me there might be "dust" in my keys, and to be careful while using my Mac (which I may add, what do you mean by "careful", am I not to eat a feet away from it or bring it any place that potentially has dust?) They also told me that supposedly the 2018 Macbook Air had fixed the notorious problem of sticky keys, and they had received no complaints.

A week later, I returned my Macbook air to replace it with a new one, sincerely hoping this was just a one-off.

Now, three days later with my 2nd Macbook air 2018, my t key barely behaves. I've loved and been an avid Macbook user for years, but this whole trial and tribulations with a brand new computer is beyond ridiculous. I just need a typeable computer, is that too much to ask?