Minor bug fixes

Author: devfresher

src/refund/refund.ts

@@ -9,7 +9,7 @@ import {
 import { BadRequest } from '../interface';
 
 export class Refund {
-  http: Axios;
+  private http: Axios;
   constructor(http: Axios) {
     this.http = http;
   }

src/transfer/transfer.ts

@@ -18,7 +18,7 @@ interface BadRequest {
 }
 
 export class Transfer {
-  http: Axios;
+  private http: Axios;
   public control: Control;
   constructor(http: Axios) {
     this.http = http;