SMS Confirmation color for Twilio

How do I change the sms failed or success return message from green to white?

To clarify, do you want to change the Twilio SMS template color? Unfortunately, there is no option to change the return message color.

can i change the colour of that particular block then so the text can be
seen? without changing the coloiurs of the other blocks?
...

My apologies, I can't seem to follow your requirements.

To clarify, do you want to change the color of your competition code field?

Or are you referring to the SMS message?

I want to change the colour of the background where the failed or sucess
message is displayed so it can be seen.
...

To clarify, are you referring to this text?

Unfortunately, there is no option to change the warning text's color or fonts in the Card form.

Sorry you misunderstood. All these modules come on blocks. A name block,
email block telephone block etc. Can I changer the background colour of a
single block like the telephone block? Without affecting the colours of the
other blocks
...

It's currently not possible to change the background color of each block. It will always remain in white color. You can only change the body background color, button text color, button background color, thank you page background color.

If you want a full color of the design, you can switch to classic form layout https://www.jotform.com/help/488-How-to-Change-Form-Layout. 

Let us know if you have any questions or if you need further assistance.