Step 1: Know the duty.
Under the CPC, 1908, the plaintiff must take the steps needed to move the suit forward, including paying court fee and postal charges for serving summons.
Step 2: Understand summons.
The defendant must be served with summons. For this, the plaintiff deposits the process fee and postal charges within the time the court allows.
Step 3: See the effect of failure.
If the plaintiff does not pay within the time granted, it shows the plaintiff is not pursuing the suit.
Step 4: Find the consequence.
The CPC lets the court dismiss the suit for this default.
Step 5: Rule out wrong options.
The court need not return the plaint, stay proceedings, or decide on merits when the plaintiff has failed to pay these charges.
Step 6: Final answer.
The court may dismiss the suit.
\[ \boxed{\text{Dismiss the suit.}} \]