wi fi texting 5c

Sorry. I still get the terminology wrong-I am having trouble sending/receiving iMessages to others who also have iPhones. I was under the impression that I COULD send msgs.without using my cell data if I had a good wifi connection. Have been doing so (without cell data on) for a couple of years. Also thought that if I sent iMsgs. to others with an iPhone that the msg. box/text was blue-denoting another similar phone. I cannot send/receive iMsgs from others. Hope that clarifies a bit. I'm not a tech anything expert-I know just enough to get myself in a jam. Thanks for any help. If I'm using the incorrect terms, please excuse-and let me know what I should be using.. Thanks.

Greetings, again, Templeton Peck.. I continue to have a problem with sending/receiving texts and messages.Perhaps I didn't explain fully. Up until recently, I never enabled my cellular data on my 5c iOS 8.3 unless I was away from a wifi connection.When I had a wifi connection, I was able to send AND receive text messages from everyone in my contact list. The texts/msgs. I sent (and received) to those who had iPhones always were in the "blue bubble"-which meant I was not using my allotted cell data. For those who did NOT have an iPhone, all were the green bubble. I had changed none of my settings.

I have had 3 "help" conversations with Apple CS reps in the last 3 days. In each, I was advised to enable iMessage, SMS, and MMS., all of which had always been checked. In my 1st conversation, (1 1/2 hr.) I was told to first set up an icloud acct (I already had an Apple ID), back up everything, and restore from the cloud.Which I did-with no change. In my 2nd conversation , another rep, another 2 hrs., I was advised to back up, then delete all network settings, and perform a restore from the cloud. I did, with same result. 3rd conversation of 2 hrs., advised me to backup to cloud, delete ALL, and then restore. Which I did. Again. Then I was told that if I AND my contacts with an iPhone did not BOTH enable iMessage AND cell data, then all texts/msgs. would be using cell data., hence all would be sent/received in the green bubble. Had to reinstall my (few) apps, and reset my preferences. Then I noticed that my voicemail is not working-I get a message advising me to "contact my carrier".

Now ,the only thing I have changed-and that ONLY after the problems began,was to enable icloud. I still cannot send/receive texts/messages from other iPhone users unless cell data and iMessage is enabled. Until recently,THAT was never the case. I hope I clarified enough for you or someone else to be able to offer a solution. I see by clicking your name that you are a frequent poster-that's why I returned to my initial post. Hope I haven't offended-certainly not my intent. I'm merely hoping that I can restore my previous functionality without incurring added expenses. My thanks and heartfelt gratitude to any who have answers.