Purchase details in Table 4A of GSTR 4 , will be auto populated form GSTR1 , filed by the supplier , I think same you have to Verify form your Books of Accounts , just confirm and reply .
If they are not auto opupated in Table 4A of GSTR 4 means , supplier may not have filed GSTR1 , just you have confirm from supplier , because if you purchase from registered supplier he will file GSTR 1 .