If you have a PayPal account make sure you have at least TWO up-to-date phone numbers registered with them because if one changes or stops working for any reason you will need the other to login.
My mobile number expired before I could update it but fortunately for me I was able to use my landline number to verify login.
Others have been less fortunate and found themselves PERMANENTLY locked out of their account after their mobile number changed and received little if any help from PayPal.