If really stuck, seek advice from your local Citizen's Advice or Trading Standards Officer. If all else fails take them to the small claims court or seek publicity in Local or national newspaper.
If the pram is not delivered or the money returned that is theft on the part of TKMaxx. As others say, describe your plight on social media.
I found this website that will help you resolve your problem. www.resolver.co.uk/companies/tk-maxx-complaints/contact-details
Where can I donate a wheelchair apart from the tip?


