SMS on MY PC

No error messages at all. I just type the phone number, that I know is correct both mine and my wife's using @tmomail.net. I have both numbers in contact list and know they are correct. I send them through Outlook that MS states it is performing correctly as they had access to my PC and made sure all was functioning and up to dat. Once I type in where I want to send it I add a picture, documents, etc. non of which never make a MB in size. I have even tested by just typing a sentence in the body. I then select Send, and my outbox shows sent. After that I have no idea where it is. I never get any error messages, Undeliverable, nothing. I send it and it is just gone. Previously it was a week to week thing. It would go and then received. for the past month it hasn't worked at all. Not thrilled paying for a service that has a application that should work, has worked intermittently but now nothing. If you check my account you will see that it really got bad around January and was getting worse, unpredictable, and I was never sure if anyone got stuff I sent. I didn't not realize just how much I used this feature until I was told basically "Oh well not T-Mobile issue, sorry for the inconvenience."