If you can at all - go to an office in person.  I have to say I've always found the staff in the office in Tortosa great.  Before I upgraded supply to house, the meter was inside and the readings were estimated for years so were always worng.  I had to go regularly to the office and while I can speak spanish, I know of other people who have been able to communicate pointing at bill, shaking head at meter reading, writing down correct reading etc.  Better do it in person if possible.