public boolean isInInventory(String serialNumber, MainFrameXLS frame){
		String status = "";
		loadSheets();

		//Check if number is ICCID of a card
		if(serialNumber.length() >= 6 && serialNumber.substring(0, 6).equalsIgnoreCase("089351"))
			serialNumber = serialNumber.substring(2);


		for (int i = 0; i < serialNumberColumn.length; i++) {
			if(serialNumberColumn[i].getContents().equalsIgnoreCase(serialNumber)){
				status = "Ref. SAP: "+sheet.getCell(REF_SAP_COLUMN, i).getContents()+"\n"+
						"Description: "+sheet.getCell(DESCRIPTION_COLUMN, i).getContents()+"\n"+
						"S/N: "+sheet.getCell(SERIAL_NUMBER_COLUMN, i).getContents();

				Label label = new Label(VALIDATION_COLUMN, i, "OK"); 
				try {
					wrWorkbook = Workbook.createWorkbook(new File(super.getFilePath()), workbook);
					wrSheet = wrWorkbook.getSheet(0);
					wrSheet.addCell(label);
					
					writeToTXTFile(serialNumber);

					wrWorkbook.write();
					wrWorkbook.close();
				} catch (RowsExceededException e) {
					e.printStackTrace();
				} catch (WriteException e) {
					e.printStackTrace();
				} catch (IOException e) {
					e.printStackTrace();
				}

				frame.updateStatus(status);
				return true;
			}
		}
		status = "Item with S/N "+serialNumber+" is NOT in inventory!";

		frame.updateStatus(status);
		return false;
	}