fix monthly usage query

apps/web/src/server/api/routers/billing.ts

@@ -1,6 +1,6 @@
 import { DailyEmailUsage, EmailUsageType, Subscription } from "@prisma/client";
 import { TRPCError } from "@trpc/server";
-import { format } from "date-fns";
+import { format, sub } from "date-fns";
 import { z } from "zod";
 
 import {
@@ -28,15 +28,16 @@ export const billingRouter = createTRPCRouter({
     const isPaidPlan = ctx.team.plan !== "FREE";
     let subscription: Subscription | null = null;
 
-    if (!isPaidPlan) {
+    if (isPaidPlan) {
       subscription = await db.subscription.findFirst({
         where: { teamId: ctx.team.id },
         orderBy: { status: "asc" },
       });
     }
 
-    const isoStartDate =
-      subscription?.currentPeriodStart || format(new Date(), "yyyy-MM-01"); // First day of current month
+    const isoStartDate = subscription?.currentPeriodStart
+      ? format(subscription.currentPeriodStart, "yyyy-MM-dd")
+      : format(new Date(), "yyyy-MM-01"); // First day of current month
     const today = format(new Date(), "yyyy-MM-dd");
 
     const [monthUsage, dayUsage] = await Promise.all([