Did you top up by at least £10 during your part of the activation process?If so,it can take upto 24 hours for activation to fully complete (generally a lot quicker,though).
Hey please do not worry or stress. Although giffgaff are generally super quick at activating sims, sometimes it can take up to 24 hours, please sit patiently, i understand it's frustrating but maybe the payment from your bank hasn't been fully processed just yet.
Thank you! x