Credit given to wrong party in 2018-19

hello,

By mistake in gstr1  of august 2018 we have mentioned gst number of customer b instead of A.

the invoice bears the correct gst number of A, the error is on the portal.

Since we cannot rectify it now on the portal what is the possible;e solution to this ?

can customer a claim it or will they have to reverse it ?

customer whose gst number was mistakenly mentioned has not claimed it