Following Apple support pages have links to sales, support, and other details.
Maybe the place to look through, for Apple 'authorized reseller' in Thailand?
• Apple - Find Locations - Thailand > Sales, support, AASP, service, etc (en)
https://locate.apple.com/th/en
• Apple Store - Apple Retail
https://www.apple.com/th/retail/
shows ^ two 'apple' stores in bangkok
• Contact - Official Apple Support
https://support.apple.com/contact
• Shopping Help - Apple (online)
https://www.apple.com/us/shop/goto/help
• Store List - Apple Store - Apple (official Apple?)
https://www.apple.com/retail/storelist/
Bangkok, Iconsiam
299 Charoennakorn Road
Khlong Ton Sai, Khlong San, Bangkok 10600
1800 019 447
Bangkok, Central World
4, 4/1-4/2, 4/4 Ratchadamri Road
Pathumwan, Bangkok 10330
1800 019 448
IF you need to contact 'official Apple, Thailand' try online links & local phones.
Sorry to not be able to sufficiently be of assistance; this is not my day job.
