Hi there
I have been through the thread and saw someone had a similar issue but I followed it all and no resolution.
1) It was working fine when I installed my new payment gateway "ipaybySSL" by SCNET.
2) needed to fix the page where customers can change delivery address so resolved this as a result of this updated my old version 1.0x to the latest and followed installation instructions to the tee.
3) Now I get the error: Your order's details have changed. Please review the current values and re-submit.

Running zen version 1.5.4
ozpost module and the winchester responsive template.
As it is late here 2.21am I have had to turn the module off just in case some people try and purchase when there is not an issue with payments going through.
but when I wake up I can turn it on if you need to test it.
The website is www.jarsbottlesdirect.com.au
thanks in advance for your help