Linking accounts

Hi. I have a problem. I have a WT account by e-mail. I have a WT mobile account registered to the same e-mail and nickname. I also have another War Thunder Mobile account assigned to a GooglePlay account. On the WT mobile account with GooglePlay I have several machines that I can import to normal WT. Unfortunately, when I try to add an e-mail on the WT mobile account associated with the Google Play account to associate it with an existing WT e-mail account, it displays busy. Unfortunately, I do not know how to delete a WT mobile account without deleting the WT account. I wanted to delete the WT mobile account associated with the same gmail address as on the PC to free up space and connect the PC e-mail account with the WT mobile account on GooglePlay. What should I do?

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