First check your email. If you used Or email a copy to yourself on the receipt page, the receipt and your rights link are in that inbox. The subject reads "Your consent receipt" followed by the firm's name. Look in your spam folder too.
If you did not email it to yourself, nothing we hold can bring it back. The rights link is made once for each consent and shown once, on the receipt. We keep only a fingerprint of it. Nothing in our service can show the link or send it again, and the firm cannot see it either. We therefore cannot tell which link was yours.
Losing the link does not end your rights. The firm can act for you from its own records while your consent is still in force. It can withdraw the consent for you, and the withdrawal takes effect at once, with the same result as one you make from the link. It can also record a request from you for a copy, a correction or deletion. Asking for your data rights explains how those are answered.
To reach the firm, use the contact details you already have for it. Your upload link can also help. If you finished, opening it shows a short message that nothing more is needed from you, with the firm's name. Under Grievance contact, it shows the name and email address to write to. If we emailed the request on the firm's behalf, a reply to that email also goes to the firm's grievance contact. Tell the firm your name as it has it and the request it sent you.
If you sent only some items and never finished, you were not given a receipt or a rights link, so you have not lost either. Open your upload link to add the rest while it is open.