Section 1689.6 is the cooling-off right, and unlike rescission under § 1689 it needs no reason at all. Paragraph (a)(1) gives the buyer, in addition to any other right to revoke an offer, the right to cancel a home solicitation contract or offer until midnight of the third business day — or midnight of the fifth business day if the buyer is a senior citizen — after the day on which the buyer signs an agreement or offer to purchase that complies with § 1689.7. Paragraph (a)(2) applies the same periods to contracts written under Business and Professions Code § 7151.2, running instead from receipt of a signed and dated copy of the complying contract.
The phrase "which complies with Section 1689.7" is the part that matters most in practice. Section 1689.7 prescribes what the contract must contain — the notice of the right to cancel, in the required form and language, together with a cancellation form. Where the contract does not comply, the three or five days do not run from signature in the ordinary way, which is how a buyer can still be within the right long after the transaction. Paragraph (a)(3) treats service and repair contracts under Business and Professions Code § 7159.10 separately, tying cancellation to receipt of a complying contract and the commencement of the work.
Subdivision (b) gives a longer period — until midnight of the seventh business day — for the purchase of a personal emergency response unit. The five-day senior citizen period applies to contracts entered into, or offers conveyed, on or after 1 January 2021. What the section does not do is define "home solicitation contract"; that is § 1689.5, and it turns on where the contract was made and how the sale was solicited rather than on what was sold. Whether a particular sale is within the scheme, and whether the clock ever started, is worth checking with a lawyer or a consumer agency quickly, because the periods are short when they do run.