How do you set Promotions? How do you change contact details?

Hi, I’m hoping someone can help me with two questions please. I’ve been going around in circles this last week with the agents on the chat desk and still haven’t got anywhere so hoping this alternative might result in a better solution.

The first question is regarding promotions/discounts. I’ve been told two different methods by various different agents, which were:

"In order to apply promotion,

1. Go to seller central > Manage inventory > Search with ASIN
2. Click on “Edit” on right side
3. Go to offers > Scroll down
4. You have to mention the original price in the box beside “Your price”
5. And enter the discounted price in the box beside “Sale Price”
6. Then you would be able to see the promotion with live detail page"

and

"The process to create a promotion is : seller account > under Advertising > click Manage Promotions. On the Create a Promotion tab, click the Create button for the promotion type you want to offer.

To clarify: I am talking about on a listing, when you see a product as a customer and it has the original price crossed out, “X% off” and then the discounted price next to it. Are either of these methods above in relation to that? I asked this direct question repeatedly and don’t know if I wasn’t explaining the question properly to them, if they didn’t understand me, they are reluctant to tell me, or something else.

The second question is regarding email. I have updated my email address in the following spaces:

https://sellercentral.amazon.co.uk/notifications/preferences (Amended them in all sections of the ‘Notification Options’ tab as well as the ‘Contact’ tab on that page)

and

https://sellercentral.amazon.co.uk/sw/AccountInfo/SellerProfileView

However, the log in email remains the old address (not too fussed if this can’t be changed though) and all my chats and emails with the help desk (and probably the forums too, though this is my first post so not sure yet) are being sent to the old address as well. Is there another section where I have to amend the address specifically for help desk issues? And if so, could someone provide the link please? (And also, if anyone knows any other links where I would also have to amend an email address for something else, could someone provide those as well?)

I have raised the above issue at least four times now and each time I’ve been told someone will look into it and get back within 24 hours, but every response has just been instructions on how to change the address along with links I have already given above and have already amended the email address there. Hoping I can get help here.

Thanks for reading.