The phrase "has been fully paid" is correct and usable in written English. You can use it to indicate that an amount owed has been completed paid. For example: The invoice for the new chairs, which was due on the 10th, has been fully paid.
The mortgage has been fully paid.
He has been fully paid the amount we owed.
At least one of Mr. Sharpton's recent debts has been fully paid.
"Bank of America's $10 million commitment has been fully paid," said Nicole Nastacie, a spokeswoman for the bank.
She has no idea if she and her four siblings will ultimately inherit any equity in the home, which had been fully paid off before the scheme.
The public improvements suggested in the president's proposal would have been fully paid for by the bill's tax surcharge.
The reporter then realized that she had in effect become a hostage, like all the other migrants, until he checked that all her fees had been fully paid.
Ludwig does not simply clarify my doubts with English writing, it enlightens my writing with new possibilities
Simone Ivan Conte
Software Engineer at Adobe, UK