Changing mobile phone, i lost all my data.

I connected a new phone to the garmin. At a certain moment It sync the two new activities so online I saw all the old activities + the new.

In the mobile APP I had only the last two days.

Then I reconnect online today and all the past activities disappear.

I seems the account in the App, on the new mobile phone, first sync the two n-ew activities on the web, but it doesnt' sync back with the web activities.

Then it updates the web with its own state, with all the back activities DELETED. 

I lost everything. Ho can I recover My activities in the internet account and the mobile app?

Thank you