I've used Tax Act (full version paid for) - for the last 2 years - all without a US address or phone number.
What I did was use what is known as a white address (when paying by credit card) as the work around on paying by UK credit worked for me using a white address (the TaxAct city, state & zip code, but your actual UK street address). I was charged so, no issues from Tax ACT.
For a phone number I enter my UK mobile number without the leading 44 or 0 - this actually creates a legitimate number from my perspective but clearly one that doesn't work in the US - (for me area code 791 does not exist!) Tax Act will attempt to send a validation code as a text, but they also send the same code via email - use that and you're in!
Good Luck