diff --git a/src/ZGoBackend.hs b/src/ZGoBackend.hs
index 7cf505f..6b52d25 100644
--- a/src/ZGoBackend.hs
+++ b/src/ZGoBackend.hs
@@ -523,9 +523,16 @@ upsertPayment pipe dbName p = do
               (memo p)
       let payment = val payTx
       case payment of
-        Doc d ->
-          access pipe master dbName $
-          upsert (select ["txid" =: txid p] "payments") d
+        Doc d -> do
+          results <-
+            access
+              pipe
+              master
+              dbName
+              (rest =<< find (select ["txid" =: txid p] "payments"))
+          when (null results) $
+            access pipe master dbName $
+            upsert (select ["txid" =: txid p] "payments") d
         _ -> return ()
 
 authSettings :: AuthSettings