$delta = $pi->delta();
$piWrapper = entity_metadata_wrapper('paragraphs_item', $pi);
$field = $piWrapper->field_name->value();
$host = $pi->hostEntity();
$hostWrapper = entity_metadata_wrapper('commerce_product', $host);
$hostWrapper->$field->offsetUnset($delta);
$hostWrapper->save();
$piWrapper->delete();

$hostWrapper->$field->offsetUnset($delta);
$hostWrapper->save();

$hostWrapper->$field[$delta]->set(NULL);