add refund faq entry, update custom plan entry (#3059)

Author: dstaley

docs/guides/billing/overview.mdx

@@ -41,6 +41,10 @@ Clerk Billing only uses Stripe for payment processing. You can see payment and c
 
 No. Stripe accounts created for development instances are sandbox/test accounts and cannot be used for production. For a production environment, you must create a separate Stripe account.
 
+### Does Clerk Billing support refunds?
+
+No, Clerk Billing does not support refunds at this time. You can still issue a refund through your Stripe account. Please note that refunds performed in Stripe will not be reflected in income/MRR calculations.
+
 ### Is Clerk a Merchant of Record (MoR) for transactions?
 
 No, Clerk does not provide this service.
@@ -55,7 +59,7 @@ None directly, but since payments are processed through Stripe, you can use any
 
 ### Can I offer custom pricing plans to specific customers?
 
-Clerk Billing does not currently support custom pricing plans, though we plan to roll out support for this in the future.
+Yes, Clerk Billing supports custom pricing plans. See [Custom Plans and prices](/docs/guides/billing/custom-plans) for more information.
 
 ### Can I let users upgrade or downgrade their plans mid-cycle?