hey, i am having a problem with the rating thing , so i sold a lot of things but there are so many buyers who complete the transaction but they dont rate me , is that normal? i have a bunch of an unrated transactions , is there an auto-rate system or something?
"Note that the Buyer has 3 days after the delivery date to decide on the acceptance of your item.
If the Buyer does not complete the transaction after the 3 days, the transaction will be deemed to be complete and final. The system will submit an automatic “Good” rating for you after you revisit your listing following the 3 days. To revisit the listing, just tap on the listing and the Automatic Buyer Rating will go through. Then you can submit a rating for the Buyer.
Note: the 3 days auto-completion is fixed on Gameflip’s system. Our support team cannot reduce it."
Lucy 
In your listing description or exchange messages, you can ask/remind them to rate you after completing their purchase.
This is true but some people still wait the 3 days because they forget or lazy or wait to use the gift card.
Just make sure to word it correctly so people understand you
Yes you can ask people to rate you after but there is no guarantee people will do it.
Lucy
@CidxLucy i know that i wait 3 days then i click on the listing i recieve the money but not the rating, i never got the rate
If You completed the trade and the buyer didnt put any rate then he wont be able to do it. He has to do it immediately
so, no solution for that?
Ask @DunnBiscuit
thanks anyway.
The buyer has around 30 days to rate you after the transaction was completed. Likewise, you also have 30 days or so to rate the buyer.