lost

Cant unpair my lost mi band 4 from device, cause obviously i don't have it anymore :') How can i do it? Is there a tech support who can help? I can't pair new mi band because of this :(

Hi all. I tried to find some help in a spanish forum I usually visit, but is no help, I think the case I have is quite rare and strange. I have never read before about. 2016's black friday I had a friend searching for a phone, and I achieved a quite cheap Mi5 for him. Is 3gb ram and 32gb...