IMessage and Facetime activation failed

i woke up this morning and replied a few messages through iMessage but my friend asked if I had changed my email as my iMessage stopped working with my mobile number.

Subsequently, my iMessage and facetime activation failed and I couldn't reply or receive any messages. This has been going on all day and I've done everything that the support team suggest but it's still not working. It keeps saying activation failed.

Does anyone know how to fix this?