I am trying to enable the rate-limit for my istio enabled service. But it doesn't work. How do I debug if my configuration is correct?

apiVersion: config.istio.io/v1alpha2
kind: memquota
metadata:
  name: handler
  namespace: istio-system
spec:
  quotas:
  - name: requestcount.quota.istio-system
    maxAmount: 5
    validDuration: 1s
    overrides:
    - dimensions:
        engine: myEngineValue
      maxAmount: 5
      validDuration: 1s
---
apiVersion: config.istio.io/v1alpha2
kind: quota
metadata:
  name: requestcount
  namespace: istio-system
spec:
  dimensions:
    source: request.headers["x-forwarded-for"] | "unknown"
    destination: destination.labels["app"] | destination.service | "unknown"
    destinationVersion: destination.labels["version"] | "unknown"
    engine: destination.labels["engine"] | "unknown"
---
apiVersion: config.istio.io/v1alpha2
kind: QuotaSpec
metadata:
  name: request-count
  namespace: istio-system
spec:
  rules:
  - quotas:
    - charge: 1
      quota: requestcount
---
apiVersion: config.istio.io/v1alpha2
kind: QuotaSpecBinding
metadata:
  name: request-count
  namespace: istio-system
spec:
  quotaSpecs:
  - name: request-count
    namespace: istio-system
  services:
  # - service: '*' ; I tried with this as well
  - name: my-service
    namespace: default
---
apiVersion: config.istio.io/v1alpha2
kind: rule
metadata:
  name: quota
  namespace: istio-system
spec:
  actions:
  - handler: handler.memquota
    instances:
    - requestcount.quota

I tried with - service: '*' as well in the QuotaSpecBinding; but no luck.

How, do I confirm if my configuration was correct? the my-service is the kubernetes service for my deployment. (Does this have to be a VirtualService of istio for rate limits to work? Edit: Yes, it has to!)

I followed this doc except the VirtualService part.

I have a feeling somewhere in the namespaces I am doing a mistake.