Hi everyone, I just resolve the issue with an email to apple support, just like this:
"I have a trial period of Apple Music, I need to cancel this membership in order to reactivate later again on my new store. This request is because I need to add my local credit card and pay by this method my futures purchases. I appreciate your support. Thanks a lot."
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I receive this answer:
"I see that you’ve already switched your iTunes Store account to XXXXXX and re-subscribed to Apple Music. Upon checking, I was able to confirm that you had been charged for the re-subscription to Apple Music as the free trial had already been used the last time you had your account under iTunes Store US.
Apple Music is device and account specific, which means that the free trial membership can only be used once. A subscription to Apple Music gives you access to the Apple Music library, expert recommendations, and unlimited skips on our radio stations. For the full list of Apple Music features, see this page:
http://www.apple.com/music/membership
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Unfortunately they charge me my Apple Music subscription, can´t longer use the free trial because I have use it in my other country store.
Hope this works for you people too.