How to stop duplicate rows?

i have a problem in my code where if i do import operation, i always get duplicate rows of imported value. What are the problem in the codes below and how to fix the problem so when i do import operation it won’t get duplicated?

import.php

class SubmissionDetailImport implements ToModel, WithHeadingRow
{
    protected $id;
 
    function __construct($id) {
            $this->id = $id;
    }
 
    public function model(array $row)
    {
 
        $spreadsheet = IOFactory::load(request()->file('file'));
        $i = 0;
        foreach ($spreadsheet->getActiveSheet()->getDrawingCollection() as $drawing) {
            if ($drawing instanceof MemoryDrawing) {
                ob_start();
                call_user_func(
                    $drawing->getRenderingFunction(),
                    $drawing->getImageResource()
                );
                $imageContents = ob_get_contents();
                ob_end_clean();
                switch ($drawing->getMimeType()) {
                    case MemoryDrawing::MIMETYPE_PNG :
                        $extension = 'png';
                        break;
                    case MemoryDrawing::MIMETYPE_GIF:
                        $extension = 'gif';
                        break;
                    case MemoryDrawing::MIMETYPE_JPEG :
                        $extension = 'jpg';
                        break;
                }
            } else {
                $zipReader = fopen($drawing->getPath(), 'r');
                $imageContents = '';
                while (!feof($zipReader)) {
                    $imageContents .= fread($zipReader, 1024);
                }
                fclose($zipReader);
                $extension = $drawing->getExtension();
            }
 
            $myFileName = time() .++$i. '.' . $extension;
            $path = storage_path('/app/public/images/detail/');
            file_put_contents($path . $myFileName, $imageContents);
 
            SubmissionDetail::create([
                'submission_id' => $this->id,
                'nama_barang' => $row['name'],
                'image_path' => '/public/images/detail/' . $myFileName,
                'jumlah' => $row['quantity'],
                'harga_satuan' => $row['price'],
                'harga_total' => $row['total_price'],
                'keterangan' => $row['description'],
            ]);
        }
    }
}

importcontroller.php

public function import(Request $request) {
        Excel::import(new SubmissionDetailImport($request->id), $request->file('file'));
        return redirect()->back()->with("status", ["status" => true, "message" => "Success importing detail"]);
    }