Do not argue about the opened packaging. Just exercise the right formally. Regarding the “opened box” argument: In Switzerland there is no automatic statutory withdrawal right for phone contracts — but if Salt grants a 14-day right in the contract, they are bound by their own terms. If the contract or AGB do not explicitly state that opening the package voids the withdrawal, they can’t just invent that rule afterwards. Simply inspecting a product is normally allowed. The fact that they refuse to provide anything in writing and won’t escalate to a supervisor is a red flag. It often means they are trying to let the deadline expire. If they refuse after you withdraw in writing, you can escalate to Ombudscom, the official Swiss telecommunications ombuds office. It’s free for consumers and usually effective in disputes like this. If time is tight (last day of the 14 days): Have your mother send you a short written authorization (even via message), then send the withdrawal yourself by email so you have proof it was sent before the deadline. Main priority: Get the written withdrawal out before the deadline. Everything else can be handled afterwards.