You are looking for anticipatory repudiation [1]. The Uniform Commercial Code in the U.S. regulates this and says the seller can collect damages as you'd expec

You are looking for anticipatory repudiation [1]. The Uniform Commercial Code in the U.S. regulates this and says the seller can collect damages as you'd expect. I think if a company tried to say "you can only cancel this contract if you personally serve it to our CEO who by the way is on vacation in the Caribbean so you'll have to fly down there" - that is, making it difficult to notify the seller of repudiation, then the court would probably find that unconscionable. I think as to what forms of notice are appropriate, it's probably instructive to look at related things like due process requirements for notice [2]. As I think about it, the mail system is probably the most standard system for entities (corporations, people, state governments, etc.) to notify each other about things, so just intuitively I would find it hard to believe that a company could get away with refusing a mailed repudiation of contract. I don't think for example you could send your repudiation through Twitter and expect it to be legally binding however. The important part is you put the other party on notice that you have repudiated the contract, and the due process example is interesting because satisfying due process doesn't require "actual notice" [3]. [1] https://en.wikipedia.org/wiki/Anticipatory_repudiation https://en.wikipedia.org/wiki/Anticipatory_repudiation [2] https://en.wikipedia.org/wiki/Jones_v._Flowers https://en.wikipedia.org/wiki/Jones_v._Flowers [3] https://en.wikipedia.org/wiki/Actual_notice https://en.wikipedia.org/wiki/Actual_notice