Buy a cooker. Pay delivery, pay for install. Its faulty within 30 days. Currys are legally obligated to refund. However, if you are unable to use a telephone, they offer no other alternative to resolve the issues they are legally obligated to. Try to complain, again only telephone and by post.
They are not only in breach of the Equality Act 2010, but also the Consumer Protection Act. I will never buy from Currys again
Recommendation: Avoid Currys. There are many more retailers out there