Which sim card hosting with response option to choose?

Question

SMS

The task was to organize an SMS service. That is, the phone number to which you can send a request, and he will give an answer.
I already had a similar service, based on headwind sms-communicator. But it all works, to put it mildly, unstable.
This is a bundle of a usb modem, a program, and a web service. That is, SMS comes to the SIM card, the program intercepts it, processes it and sends it to the web service, where all the logic is carried out.
The most unreliable thing here is the usb modem - it periodically fell off, I still could not achieve uninterrupted operation. Well, because of this, I didn’t hang important tasks on all this disgrace. But now it is necessary.
I began to look for SIM hosting, but it is somehow incomprehensibly expensive - 2 tons per month is unclear for what. And few people allow you to send SMS from these sims - only receive. Virtual numbers immediately disappear, since it is basically impossible to send from them - now such messages are blocked by operators.
According to the results of the research, I realized that the most reliable and budgetary now seems to be an android program that will receive SMS from the phone and redirect it to a web service. Well, to receive messages from him for a response.
It was at this stage that I got stuck - I did not find anything suitable and with good reviews.
I would be very grateful for advice - in which direction to move. Thanks in advance!

Answer 1

Wow, the question is two years old, I forgot about it)
The question was resolved as follows:
1. The server to which the industrial modem is connected is the same type that is installed in payment terminals. There are quite a few options, I chose IRZ MC52iT
2. on the server, the headwind sms-communicator
3 program. It communicates with a self-written web service that has an api for sending and receiving SMS.
The bundle has been working without a single failure for six months.
It should be noted that all operators in the terms of use have a ban on automatic processing of SMS by various services. If there are few messages, no one will pay attention. If there are too many, they will block.

Answer 2

We also wrote a program for android and used a regular smartphone.