Intermittent no start issue

Hi,

I have the car listed above that doesn't start at times.

I thought it was the petrol pump.

I took it to a Nissan workshop and they said that its not the petrol pump, it is the battery.

After they brought the car back, it drove with no problem for about a week and then decided not to start again.

Any ideas?

Please, thank you.

Giesela