You may have noticed several line items on your receipt and are confused. Rest assured, this is normal, and you aren't being overcharged.
These line items are users being added and removed from the Matter-connected channel.
For context, billing plans are pro-rated daily based on the number of channel users. The invoice amount will be automatically adjusted and charged at the end of the billing cycle to the payment method on file. A decrease in channel users (i.e., someone leaves) will result in a credit towards the next invoice amount.
In other words, you'll only pay based on the number of channel users and how long they are in the Matter-connected Slack/Teams channel.
Here's a video explaining in more detail: