Approve IOS App

I have an IOS app that has a subscription feature. The app has payment gateways like Paypal, Apple In App purchase. etc. The app was approved by the Apple along with the external payment gateways but now the new version has been rejected by the Apple with a reason that the payment methods other than Apple In App Purchase is not allowed.

I need someone who can get the app approved along with the external payment gateways.