Does saying 'a letter was sent' have any weight in contract law?

[sayre]

Or would there need to be proof like with a registered letter.

For example, giving someone written notice in a tenancy

or this instance (which is my situation)

A company is required in a contract to do something and after an original acceptance of terms, is later asked why they did not complete says they sent another letter to you saying that we required you sign a new acceptance by this date due to changing circumstances. If the letter never arrived, would they need to prove the letter was posted/received to get out of their obligations past the due date?

[ezri]

The specific law of your state with resolve your question, but many states have statutes or case law decisions which hold that proof (such as oral testimony) of putting a letter in the U.S. Mail creates a presumption that the letter was received by the addressee, but that presumption can be rebutted by proof that it was not received; it is then up to the trier of fact (judge or jury) to decide which proof is to be believed. The "need to prove" (which lawyers call the "burden of proof") is a different question, though, and depends on whether the proof is needed to support a claim, to support a defense, in rebuttal, etc.

[ardwyad]

In most cases a company with just send a letter. That's considered an acceptable form of communication. If everyone agrees that the letter was sent and received, then that is considered a legitimate form of communication.

It's only a problem if the one party claims that they never received a letter. In such a case it's helpful to have proof, like a registered letter or a returned signature. If there's no proof that the letter was received, then it's up to the judge to decide.

There are situations where a registered letter is required by law. But in most cases it's not required, it just makes it easier to prove in court. Generally a company will only bother with a registered letter when they think there's a possibility of going to court.