Texts to International numbers won't go through
Hi, I'm having a significant problem trying to communicate with my international employees. I have even changed carriers over the problem, but it still persists. I can call my international employees, can receive text (sms) messages from them, and respond. However they do not get my response. There is no indication on my iphone that they did not receive the message. I have verified with my carrier that all international capabilities are functioning. They have android, I have iOS, they have cleared their cache, I have deleted their contacts, rebooted and started over. The problem persists. In fact, the more we worked on it, the worse the problem got. Now, my iphone is converting their international calls to a US format. My employee from Australia tried to call me yesterday, their country code is 61. My phone automatically placed a +1 in front of that so it identified the call as from Ohio and spam. So frustrated with this problem, ready to dump the iphone. I can't seem to find whatever will correct the problem or if it's even fixable. I've spent hours on the phone with my carrier and Apple and have turned this phone on and off at least 200 times every time they tell me to turn this or that on or off. The problem persists, I don't have my employees in my phone anymore. They can text me, I just recognize the number, I respond, they never get the text. HELP!
iPhone 11 Pro