T-Mobile iPhone users not receiving texts from my Verizon Samsung

syaoran wrote:

I text back and forth with one of my friends almost daily on Verizon.  She uses an iPhone and I am using an s23 Ultra on T-Mobile.  No issues.  Are their iPhone's up to date, including iMessage?  Apple has started blocking things from working on devices that are not up to date. 

Thank you for your reply, syaoran.

I am going nuts trying to resolve the issue.

To clarify, I have a Samsung (Android) with Verizon and the problem I’m having with people who have an iPhone with T-Mobile. 

• I found 5 people who are/were not receiving my messages. 
• They all use iPhones. I verified that 4 of them are with T-Mobile. I don't know about the 5th. 
• Other iPhone users who are with Verizon do not have the problem.
• My default messaging app is mysms, but I tried it with Samsung messages with the same result.
• In another forum, someone suggested it could be an RCS issue and that I could try turning it off. I couldn't find anything in either app about RCS. So, I downloaded Google Messages and turned on RCS Chat, and enabled the option to send as text message if RCS isn't available.
• One of the 4 contacts, who had updated her iPhone, then received my text; another who bought a new iPhone was then also able to receive my messages.
• A third still cannot receive them, and no amount of my adjusting the RCS settings works

I called Verizon. The tech refreshed everything but said I need a new sim card. I said I would go to a Verizon store to get it replaced instead of waiting to receive it in the mail. But when I went yesterday, the person there said I was still getting reception, so I don't need one, and that they don't replace sim cards anyway.