Short answer. There is a presumption, but it is rebuttable. Rule 131, Section 3 presumes That a letter duly directed and mailed was received in the regular course of the mail. A bare denial is weak against it, but the sender must first prove the letter was properly addressed and actually mailed.
What the law says
That a letter duly directed and mailed was received in the regular course of the mail
Rule 131, Section 3 — Disputable presumptions. Read the full provision →
What the law says
The following presumptions are satisfactory if uncontradicted, but may be contradicted and overcome by other evidence
Rule 131, Section 3 — Disputable presumptions. Read the full provision →
The presumption has two preconditions
Notice that the clause does not presume that any letter was received. It presumes receipt of a letter duly directed and mailed. Both facts belong to the sender to establish before the presumption does any work at all. Duly directed means correctly addressed to the recipient at the right address; mailed means actually deposited with the postal service. Prove those two things, and the law then supplies the third — that it arrived in the regular course of the mail. Fail on either, and there is nothing for the presumption to attach to.
Why demand letters turn on this clause
A great many disputes rest on whether a notice or demand ever reached the other party — a demand to pay, a notice of default, a notice terminating a contract. The recipient's incentive to say "I never received it" is obvious, and the sender usually has no way of proving what happened inside a post office. This presumption solves that asymmetry by putting the risk of ordinary postal failure on the addressee, provided the sender did their part correctly.
What overcomes it
Section 3 presumptions are satisfactory if uncontradicted, but may be contradicted and overcome by other evidence. A flat denial is evidence, but it is thin. What genuinely undercuts the presumption is proof that the address was wrong, that the addressee had moved and the sender knew it, or that the item was returned undelivered. Conversely, what strengthens the sender's position is the proof of the two preconditions: the registry receipt, the record of the address used, and any return card.
Keep the mailing proof, not just the letter
The practical failure is almost always the same — the sender keeps a copy of the letter and nothing showing it was posted. A file copy proves only that the letter was written. Retain whatever the postal service issues at the counter, together with a note of the exact address used, and keep them with the letter. That is the material this presumption is built to work on, and without it a well-drafted demand can end up counting for nothing.