GSTR-1 and 3B filed but after filing GSTR-2A reflects additional ITC

GSTR-1 and 3B filed but after filing GSTR-2A reflects additional ITC.

We did GSTR-3B on 18th but the but the seller filed GSTR-1& 3B on 20th with delay.

We didn't claim ITC since it was not displaying in GSTR-2A.

We have contacted GST they said you can claim in subsequent months.

Is there any alternative way??