I am sending texts via the NEXMO SMS api (https://www.nexmo.com/products/sms). Texts shorter than 160 characters arrive fine. Texts longer than that arrive in two parts as completely garbled hieroglyphics. Sending them in Unicode mode (even there are only ASCII characters) fixes the garbling, but reduces the maximum single text length to 80 characters. And they still all arrive as separate messages in multiple parts, and out of sequence, whereas they should be concatenated.
Just to note: NEXMO is a long established service that works perfectly when sending to other networks -- long texts are concatenated correctly and not garbled. The problem only occurs on the 48 network. I have tried sending to different phones on the 48 network, both Android and iOS and the problem occurs, so it is the network, not the phone.
Example of a garbled long text:
I reckon you'll have to contact 48 support about this.
See the link in my signature below.
Hope this helps.
No, I got three fob-off replies. 1) We don't support web texts. 2) we don't support web apps, 3) contact your app provider.
I don't think they understood this is no different to signing up for an SMS confirmation about a flight booking or a bank transaction. My own conclusion is that there are still incompatibilities across networks with concatenated SMS (https://en.wikipedia.org/wiki/Concatenated_SMS) and it's just a fact of life that the 48 network seems to be less compatible than others. Bit scary though when hoping to use concatenated SMS for important infrastructure (notifying the results of medical tests in the case I am working on).
Does it work OK to other virtual carriers on the Three network and not just to 48?
Interesting question. So far I know it works to other major networks, and it doesn't work to 48 regardless of phone type or OS. I don't have an instant way of testing those other VNOs, but I'll try to check it out. Thanks for the tip. Meanwhile I've raised a support case with NEXMO.