Buyer did not send enough money for postage. How do I send a request for the additional postage.

[brettjet38]

Info for the Buyer

https://www.ebay.ca/help/buying/postage-delivery/shipping-rates-buyers?id=4026&st=3&pos=1&query=Ship...

Increased shipping rates after a purchase

Sellers can’t increase their shipping rates after you've bought an item without asking your permission to do so. If the seller makes a change that you don’t agree with, and you can’t resolve the issue directly with them, contact us and we’ll step in to help.

Info for the Seller

https://www.ebay.ca/help/selling/posting-items/postage-rates/updating-postage-options?id=4170&st=3&p...

You can update your shipping charges after a listing has ended, but only in certain circumstances. 

Once someone's bought your item, you can't update the shipping charges from what was originally shown on the listing unless the buyer wants to pay for combined shipping for multiple items, or asks for express delivery and is willing to pay for the service.

[femmefan1946]

Did the buyer pay the amount you had advertised in your listing?

You ship and accept that this was a learning experience.

You might also want to bookmark this.

https://www.canadapost-postescanada.ca/information/app/far/business/findARate?execution=e1s1

It is best to use Calculated Shipping on anything that has to go by parcel rates.

[rocketscollectibles]

This is against eBay rules to request additional money for shipping after sales

It would turn into a scam tactic: give me $X or i don't ship

When you list your items you fix your price and agree to it by the same time. Buyer by purchasing agree to your price. You cannot change terms of sales after both ends agreed to them. You either must take the loss or dishonor your sale and cancel the order