Hi,
actually I'm confused as the requirements not clear enough. do you already have the platform and want to add to it the SMS send/receive. or you want us to create this platform from scratch? anyway I can help with both. so if you don't mind contact me to discuss all the details and give you a more accurate price and period to finish that. and I'll do that for you.
for more reference about me, you may have a look at my profile.
Regards,
Amr