I was forced to go back to injecting when my pump died.
As
@evilclive suggests, I had backup pens and remembered my dosage. So started injecting just as I used to.
Dosage for injecting is typically different to the pump so you need to know your injecting doses, ratios, etc.
One annoying thing was that I had to start my long acting insulin (Lantus) as soon as my pump failed so it was an odd time of the day. If you are choosing to go back to injections, you can chose what time you want to take it.
If you do not have a backup to your pump, regardless whether you want to go back to injecting, you
must arrange something as soon as possible. Your pump can fail at any time and you will need basal insulin. You can not rely on your DSN being available or a pharmacist being open.