How can I add MY Post Number to my seller account?

[5369gavinw]

How can I add MY Post Number to my seller account?

when I can directly to the post office I present my code at the post office I get a discount on my postage and the more I post, the greater the saving.

[davewil1964]

MyPost is independent of eBay, and using eBay labels does not count towards your MyPost spend.

You CAN link your MyPost account to your eBay account and that will allegedly upload tracking numbers to your sales.

I don't use it, it is too glitchy. I just C&P tracking numbers.