How to cancel Microsoft Mac office subscription and Skype?

I want to cancel Mac office subscription and Skype monthly pay. ( I did not use Skype for some years, but cannot find s quick way to cancel the subscription. It is a few dollars and might not worth of my time. Now with $11 more, I have more motivation) I logged into my Microsoft account and cannot find how. They cannot find my purchase history but has been charging me 11 dollars per month. I then tried to contact their bots (as I did with my bank which successfully solved my problem). To my biggest surprise, their bot could do nothing. I tried not to be critical, but after I saw the over-confusing design, I am disappointed. I cannot believe Microsoft customer service is even worse than a bank. What’s the quickest way to cancel the 2 subscriptions?