Dell Computers - unable / unwilling to honour service contract

Please engage with Dell Computers with caution with respect to technical problems and service. I purchased a Dell Vostro 5620 i7, supposedly a high-spec laptop, just a few weeks ago and it is already faulty beyond use. We all know how reliant we are on our computers for work and how devastating it can be when they crash. It was for this reason that I specifically purchased the 3-Year Pro Support, which promises next-day on-site service. The problem is Dell service technicians do NOT come the next day, nor do they even have the parts in stock! Trying to communicate with Dell (or with Compuclinic, from whom I bought the unit) to get this resolved has been unsuccessful, hence having to resort to social media. Surely this is a blatant breach of contract and the Consumer Protection Act?