Can't send Text Messages on Sony Ericsson z500A
Does the phone say "setup required" when you try to write a message? If it does then press yes to the prompt "setup now" and follow the simple steps. If that is not the case, go to messages --> settings --> text messages --> service center. Check if any number is saved there, call up your customer care and ask for the sms service center number and if no number is saved there save that number, if the number is already there verify it against the one you get from the customer care.