What should you do after identifying the cause of a billing issue?

• Explain the issue in clear customer-friendly language is the correct action. Once the cause is known, explaining it clearly helps the customer understand the situation and builds trust.

The other options are generally not the immediate next step:

• Recommending a new device is usually unrelated to a billing issue's cause.
• Reading the invoice line-by-line is part of identifying the cause, not what you do after identifying it.
• Escalating immediately is typically done if you cannot resolve the issue yourself or if it requires specialized attention, not as a default action after simply finding the cause.

The correct option is:

• Explain the issue in clear customer-friendly language