Five days later, I would still use "mustn't".
Student or Learner
2- used in negative sentences to say that something should not happen, because of a rule or law or because of the situation:
- You mustn't talk to your mother like that.
I would like to ask how I should report this sentence after days later, for example five days:
- You said I musn't/couldn't/was obliged not to talk to my mother like that. (reported 5 days later)
I think 'could not - was not obliged to' sound OK but I am not sure if 'must not' is OK. Are all OK?
Couldn't would also work, but was obliged not to does not sound natural to me.
I would use 'should not' instead of 'was obliged not to', but I am not a teacher.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.