Galaxy S6 Edge :: Phone Not Receiving Messages Greater Than 160 Characters?

I recently made the switch from an iPhone 6 to a SG6 Edge. I am loving the phone except for one key thing. I am unable to receive text messages that are over 160 characters. I know that once an SMS is over 160 characters, it turns into an MMS. But the thing is, my MMS settings are set up, everything should be working okay.

I don’t know if this matters but this phone is unlocked with Sprint, and I am currently using Rogers as my service provider. If I cant find any resolution to this I think I am going to have to switch phones either back to an iphone (which I don’t want to) or another Android phone.

Here is the list of things I have done to try to fix this problem:

-Factory reset my phone, didn’t work
-Configured my MMS and APN settings manually.
-Sent myself a picture message, received it fine.
-Sent myself a message over 160 characters, received it fine.
-Used the stock messaging app, as well as 3 different ones. (currently using textra due to the simplicity of it)
-When I had my iphone, I disabled the iMessage, also went on the apple website to make sure my phone isn’t linked to imessage. Its completely off
-Rogers said it’s a problem on the other end (contacts aren’t sending messages properly)
-this is false because I wont get any messages from android users, blackberry users, and iphone users. Its not just one or two contacts, its my whole contact list.
-few of my buddies have the S6 edge and none of them have this problem. (few switched from iphone)

The only solution I can possibly think of is getting a different sim card, but service provider said this will do absolutely nothing.

I run a business and I need to be able to receive SMS messages over 160 characters (no I will not use a 3rd party app which Samsung suggested. I need my texts to work.)