Hi , we can send you a Temporary Security Number (TSN) through the post which will reset your online banking and allow you to get logged in again. This can take between 3-5 business days to arrive and will be valid for 30 days – if you would like me to arrange this for you, please message us privately @Tesco-Bank and confirm your full name, DOB and postcode. Alternatively, you can call our Online Helpdesk anytime on 0345 300 3511 and request a TSN to be sent by text immediately once security is completed.