Problems using SMS By Now - Messages Sent as MMS

I am using SMS by now app to send group text messages as the Z10 does not allow you to create a distribution list system which previous blackberry phones did.
Recently when sending sms messages to my groups i have been prompted that the messages will be sent as MMS messages and charged for at the standard rate and not as part of my contract.
I have spoken with vodafone uk who thought maybe my messages were over 150 characters which they were not, so I sent a text message to a group with 10 characters and the same thing happens.
Vodafone have said it is not a network issue but a problem with the software on the handset and I am using the latest update.
Contacted app provider and am still waiting for a reply so I thought I would try asking you guys.

I went to download the program to try and help, but then realized it's a paid app, and since it has no utility to me I did not get it. HOWEVER reading through the reviews I saw at least one that said the company was very responsive to emailed questions, so hopefully you will here back soon. :)

Does anyone else have and know this app, that can help this new member?

Thanks Rich the company has replied and we are looking into it. Thanks again. Perri