Why my character moved to another server again?

[Shunnix.3952]

Yesterday I still play wvw at Blackgate server with friend. today my character moved to Yak's Bend server... Anet please tell me what happen... why this case happen to me again... After I create my character for the first time(2-3 years ago) I play at Blackgate Server all the time with friends... after I break about 1 years I back to play and my character moved to Maguma ... after I contact Anet about my problem Anet said can't move to blackgate because of must use gems to change. I stop play after that and about 1-2 week ago I came back to play and very happy because I back to Blackgate and I play wvw with friend until yesterday... Shock story is today I'm in Yak's Bend T-T ,It happened again.... I never change my character to another server because of my friend play in Blackgate. I never pay gems for moved server... Now I'm in Kaineng Server(I don't know why i'm here) Anet please tell me what happens + please list my playing history to me... and answer my questions ... Why my character moved to another server (not blackgate) even though I never moved once? sorry for my english thank you... My Id Shunnix.3952

[Blocki.4931]

You were never on Blackgate, you were on Kaineng all along. Server linking has changed.

[Shunnix.3952]

No not Kaineng... I play with my wife after buy HoT expansion and play together in "Blackgate Server" play WVW in Blackgate together for 2 years and today my wife still in Blackgate Server... but why I'm in another server... you understand? Especially If changing servers require 1000-1800 gems, I don't have gems enough for that.

[Inculpatus cedo.9234]

Here's some information: https://wiki.guildwars2.com/wiki/World_versus_World#Server_Linking