I'm rather worried about that website. It's a legal requirement for all UK web-traders to provide a postal address but there's not one on that website. The firm claims to be based in Manchester and there's a phone number (linked to the Chorlton exchange in Manchester) on the site. The phone number is for a valid line but the answering machine simply states that the mailbox is full and that no messages can be taken. (There's no mention of a company name on the message).
However the domain name of a legitimate UK trader will normally have been registered by the company itself or by the person running that company, usually using a British web registration service. That domain name was registered by a Panamanian company, using a Czech registration service:
http://webwhois.nic.u....x=0&WHOIS+Submit.y=0
A web search for 'electric t-shirts manchester' brings up no references to the company, other than its own website and Facebook page. (I'd expect to see a legitimate company listed in lots of trade directories).
The company claims to sell official merchandise but their prices are considerably lower than most official merchandise should be.
Regrettably I suspect that you've been conned by a fraudulent website. You can keep trying the phone number, and speak to your local Trading Standards team, but I doubt that you'll get very far. It might be worth contacting your bank or credit card company to see if they offer any protection if you've made a payment, using their card, without receiving the goods. (Credit card companies, but not banks, are legally liable to refund such payments if the amount is over £100; some companies extend that protection to lower amounts).
Chris