To 'get through' is a phrasal verb, meaning to complete something or to progress, usually after an amount of difficulty or effort.
You can 'get through to someone', meaning to reach someone by telephone or to succeed in getting a message to them. When you get through to someone by phone, you manage to speak to them. 'Getting through to someone' also has a figurative meaning suggesting you have succeeded in convincing someone else to adopt your point of view.
You can also say 'go through' when you are talking about a law, rule, procedure or an official payment. If a law 'goes through' it is approved. If a payment on your card doesn't go through, you could be in trouble.
If you 'get through' something like a big life event, it means you manage to succeed or survive a difficult or life-threatening situation. You can 'get through' an illness, or 'get through' a bad time in your life.
If you 'get through' a resource or a number of objects it means you use them up quickly.
This is a useful phrasal verb in a number of different contexts.
Addition examples with 'get through':
Someone in your family has been trying to call to make an appointment with the dentist.
"I've been trying to call all day but I can't get through. They must be very busy."
Your friend has experienced a tough break-up with her partner and some other personal difficulties.
"I know things are really hard at the moment, but we are all here to help you get through it."
A wheelchair user is complaining about the lack of access in a public building.
"The doors are not wide enough to get through with a wheelchair."