A formal reply without any useful information

Reading through the line, I can't help notice the negative feeling towards such useless response. I feel although all given answers are 100% correct, they all failed to convey such negative feeling. In this case, I think the best answer is, bureaucratic,

I was given just a bureaucratic response to my letter to the government officials.

You might call it a canned response, where can is a reference to mass-produced products delivered in tin cans - there is no customisation of its (standard) content once the can is sealed.

The sender might have several canned responses to choose from, but each canned response is a standard reply that isn't tailored to any circumstances.

Canned responses could potentially carry useful information - they are just standardised. If you want to stress the absence of specific information, you might call it a generic reply (see definition 1b: "lacking specificity"). If you want to go further and stress the lack of useful information, I suppose you could call it a useless reply. A jaded cynic might say they just received the party line.

Perfunctory Response

performed merely as a routine duty; hasty and superficial:

-- dictionary.com

In this case, "My letter received a perfunctory response" would mean that it was clearly someone's job to respond to your letter, so they did, but they didn't have to include any useful information in their response, so they didn't.