Sms messaging with Nove Modem 4G LTE


I have a nova modem running on a win7 pc. I developed code in C# for TX/Rx messages via SMS.
It works well in one direction TX it doesn’t work very well in Rx.
I can send a msg to my android phone and receive it within 10 secs.
Sending a msg from the android phone is extremely variable… Sometimes the msg takes hrs to come in other times the msg is accompanied with older msgs. Has anyone experienced the same and did you resolve the issue.