-snip-
A safe wallet to use is an open source wallet and we hold the key.

Open source is not enough to make a wallet secure, but using it can be better than using a closed-source wallet.
Consider looking at the case of libbitcoin. https://milksad.info/disclosure.html

You can see several other related links here: https://bitcointalk.org/index.php?topic=5462652.msg62672463#msg62672463.

You should never have used any closed source wallet-- but being open source is not enough.

By the way, @LibertyMask's post that you quoted was from a month ago, and he didn't even respond to user replies after that.