However, it doesn't ask the entrant for any proof of purchase. You can just make one up and choose any pharmacy. Also, this contradicts the purchase "requirement"
Entry into the Promotion is free. No purchase is necessary to enter the Promotion. Any costs (e.g. mobile phone carrier charges) associated with entering the Promotion is the responsibility of the Entrant.
Purchase required and you need to state the pharmacy where you purchased the product as part of the initial entry.