If Skype has been installed using the App Store or similar, it can easily be removed using a PowerShell command without trying to find the exact MSI command.
Get-AppxPackage Microsoft.SkypeApp | Remove-AppxPackage
The attached Fixlet uses this command in a one-line script with a simple relevance to detect if Skype is installed as registered application. Please check that this works in your environment
Uninstall Skype using PowerShell.bes (1.2 KB)