Upgrade delete all the trunks definition - Please HELP!

Hi All,
I’m having problems doing the upgrade.
I was having a FreePBX V and was trying to update to the latest stable version.
I gone from 2.5 to 2.6, then 2.6 to 2.7 and so on.
I discovered that every time I’m updating the Core module, after apply changes.
All my trunks definitions disappear and back to the default status showing only one Zap definition that came on FreePBX when you make a fresh install.

Any idea about how to fix this issue?
What steps should I do, don’t know if there is something wrong I am doing.

Thanks for the help