Make your entire billing, payment, and subscription management NOT HORRIBLE.
Skype account management was horrible in the pre-Microsft days and it's just as horrible now, mayb eworse. I got an email saying that I had to update my payment information. I went to the Skype site and it was a convoluted mess but I found a place to put credit card information. Then I waited a day or two to see if it would "take", but received another notice that there was a problem with billing.
So I contacted chat/support and they led me to entering my credit card information into the Microsoft site. But then they led me to the Skype app to click on reactivate my Skype number, which opened up Yet Another Webpage asking me for my payment information AGAIN.
Then I bought my Skype Subscription for $39/year but was then asked if I wanted to buy a subscription or calling credits. Huh? What did I just buy at $39/year but a "subscription". So I see that the "number" and "calling credits" are separate things... but they're all called "subscription".
Now I don't know what happened to my 10+ year account that it lost my payment information, or why there are seemingly THREE DIFFERENT places to put payment information, or why I was lead to all three of them.
THIS IS HORRIBLE.