Hi Snap63,
Thanks for posting on our community forums. Firstly we would like to apologise that you mum was unable to get a signal at a time when your cousin was in hospital, we can understand the concern this must have caused you all.
Can we ask what make and model handset your mother is using? Also is you mum able to make and receive calls as normal, or is the issues with calls as well as text messages?
Is the delay in text just from your number or is it any number?
We have included our network coverage checker here so you can see what coverage your mum has with us.
One last thing you may like to try for you mum is rebooting the handset, if you have not done this already. Also try her sim card in another handset to see if the same problem happens.
Kind regards Jodi.