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The discount does not apply to all products or restaurants.
Literal
All [attributive-の] products [and-及び] restaurants [at-で] discount [subject-が] take-effect [it's-not-that-わけではありません].
The negation ~わけではありません is not a flat 'none of them' — it's the partial/soft negation 'it's not the case that all,' leaving room for the discount to apply to some. 及び is the formal written equivalent of と or や ('and'), used for listing items in contracts, notices, and fine print. 効く is the go-to verb for 'to work, to take effect,' used with medicine, discounts, rules, and policies. The overall register is legalistic disclaimer.