We're very sorry to hear this.
We would recommend trying to sign up using a laptop or computer, if possible and if you're not doing so already. We also recommend using Google Chrome as your browser, and, if you still have difficulties, try clearing your cache or using an incognito window – if you’re not sure how to do so, then there is an explanation here and here.
Once you’ve tried these tips, if you’re still having difficulties, please do not hesitate to get in touch with our care team. Any extra details about what’s happening, error messages or a screenshot would be really useful in this case.