You can try using the last 4 of your ssn
if that doesn't work, then yes, you'll need to call verizon because they will have to reset/unlock the account, and they'll help you set up a new password.
Your old comcast info does not apply any longer, they have no communication with each other.
After you can access your account with the proper password, I can help you with the rest of the process for your panasonic.
I am an independent technician and I've spent my personal time, unpaid, in an effort to assist with the question for which you solicited my services. This site works on the honor system, and to that end, I have prioritized working with you ahead of other paying customers.
Although you’ve already paid your fee to the site, I am only compensated for my efforts when customers such as yourself leave positive feedback for my work. Again I apologize there is not a better outcome here, though this is really beyond either of our control. I do hope you’ll consider leaving a 5 star rating for me, rather than “shoot the messenger”, so that I may get credit for my time spent in good faith to answer your question accurately.