In app purchase 2 returns transaction data null on android

I am currently using cordova in-app-purchase-2 on my ionic app. The app was already uploaded on google console for in-app purchase testing. And the in app purchase was already showing purchase success. My problem now is that i would like to get the receipt and signature in order for me to do a purchase validation on my backend. However, the json returns something but incomplete, the transaction data is currently null. Are you able to advise? Thanks

this line of code fetch the information of a product ( where transaction data is included but currently null )

this.store.get('ionic_101')

i have tried to insert this line of code in some of the in-app purchase 2 functions but instead of returning something, it does not return a result, the only way the it can return a result is outside of in-app-purchase-2 functions. I also did insert this after the store.refresh but not luck.

senddatatodatabase(JSON.stringify(this.store.get('ionic_101')));

ex.

this.store.when(productId).approved( (product: IAPProduct) => {
senddatatodatabase(JSON.stringify(this.store.get(‘ionic_101’)));
product.finish();
this.loader.dismiss();
});