perfidy - PURR-fid-EE - faithless, a betrayal of trust, treachery
Example: "It was an act of perfidy: my keyboard died, and I spent a quarter tank of gas & half the day to find that no store carries one to fit my computer."
As a starter: and as a former teacher in English, I hope to add to reader's vocabulary by presenting a word a day in simple terms that anyone can understand - from current use in publications, radio,TV, etc. Remember: use a new word three times in a day and it's yours forever!