Or, if you are aware of the details of purchase, i.e time/date/store/price paid, then it may be possible for the store to locate your receipt in their till system.
If you have lost your receipt, but have the transaction on your bank statement, the store can accept this, alongside the same card being present.
If your item is in new, unworn condition, with the tags still attached, and purchased within the 28 day returns period, you can return it to store. Without a receipt you may be offered a credit note (for use in-store) or an exchange, at the last/current selling price of the item. Please note - Refunds are always at the Store Manager's discretion.
Please note: The above returns options refers to change of mind only and does not affect the statutory rights you have as a consumer e.g. the right to cancel, or the right to return items, which are faulty or not as described or a general right to return most online purchases under the Consumer Contracts (Information, Cancellation and Additional Charges) Regulations 2013.
For more information on your right to cancel, read here.
If you feel that your items are faulty please read more here.