why can’t I use level boost after buying war with in
Does it come up for you to use? You may need to wait till your order is done processing.
i have all the mounts but the boost is not there
Have you tried a relog?
If it’s not there in 12-24h, I’d open a ticket.
Do you have more than one WoW license on your Battle.net account? Mounts will show up on all licenses on the account, but recent boosts have been tied to the license that was upgraded. I’ve also seen people accidentally upgrade trial accounts instead of their main one, so even if you think you only have one WoW license, it’s good to double check. (If you’ve got more than one, there will be a drop down menu above the play button on the launcher that lets you select between them.)
If you did accidentally upgrade a trial account, you’ll need to see if you can get it transferred to the correct account. If you post in the customer service forum they should be able to help you with figuring out the steps you need to take in that case. (Which will probably involve a ticket.)