Firefly Dancewear reserves the right to refuse an order at any time. In general, businesses may decide for themselves with whom they wish to deal. The Competition and Consumer Act 2010 does not give anyone an absolute right to be supplied, whatever the circumstances. There is no automatic right to be supplied and there is no obligation on a business to justify its decision to refuse supply.
There are only a few circumstances that make a refusal to deal illegal under the Competition and Consumer Act. Generally, these situations only arise where your refusal to sell goods or services to someone is done for an anti-competitive reason. As stated above, these circumstances are generally limited to business-to-business transactions and are generally unlikely to occur in normal retail selling.