I'd like to know the best answer for this case?

Mary has been saving up for a new sofa for the past few months. As it is Easter weekend, she knows that there are plenty of sales on and she might find a good deal. So, Mary goes sofa shopping with her daughter on Easter Saturday. After some browsing in Sofa Store in Dublin, Mary spots a sofa that would go great with the colour scheme in her living room. She approaches Erika, the shop assistant, to enquire about the price and availability of the sofa. Erika says that the sofa is on sale at 800 down from 1,000 and is in stock. This is within Mary's budget, so she decides to purchase the sofa. At the till, Erika gives Mary a small sheet to fill out her name, address and contact details (including her email address) so that Sofa Store can deliver the sofa to Mary. Erika points out that there is a small box at the bottom and that Mary should tick it to allow Sofa Store to send Easter promotions to Mary's email. Mary explains that she doesn't want to receive such emails, but Erika says that it is only one email a year at Easter. As such, Mary agrees to tick the box. A few days later, a delivery man calls Mary to arrange a time to drop off the sofa. When the delivery driver arrives, he asks Mary how she would like to pay the 50 delivery charge. Mary wasn't aware that there was a delivery charge but since the delivery man is here, she pays the money with cash. After a few months, Mary is delighted with her new sofa but has been receiving marketing emails every week from Sofa Store. She contacts the store to ask them to stop receiving these emails. The shop assistant on the phone, Niall, says that the system shows that Mary had consented to the emails by ticking the box when she bought her sofa. If she wanted to withdraw her consent, she will have to write a letter to Sofa Store HQ explaining that she wishes to withdraw her consent and why. Identify all potential legal issues in the above scenario and briefly outline the law on that issue(s).