diff --git a/packages/numbers/lib/numbers.ts b/packages/numbers/lib/numbers.ts
index 86f788fe..bc302544 100644
--- a/packages/numbers/lib/numbers.ts
+++ b/packages/numbers/lib/numbers.ts
@@ -200,7 +200,7 @@ export class Numbers extends Client {
    * @param {NumbersSearchFilter} filter - The filter criteria for searching available numbers.
    * @return {Promise<NumbersAvailableList>} A promise that resolves to a list of available phone numbers or an error response.
    *
-   * @example   
+   * @example
    * Search for available numbers that can send SMS and make voice calls
    * ```ts
    * import { Country, Feature } from '@vonage/numbers';
@@ -306,8 +306,14 @@ export class Numbers extends Client {
     const resp = await this.sendFormSubmitRequest<NumbersEmptyResponse>(
       `${this.config.restHost}/number/update`,
       {
+        country: params.country,
+        msisdn: params.msisdn,
         ...(appId ? { app_id: appId } : {}),
-        ...params,
+        moHttpUrl: params.moHttpUrl,
+        moSmppSysType: params.moSmppSysType,
+        voiceCallbackType: params.voiceCallbackType,
+        voiceCallbackValue: params.voiceCallbackValue,
+        voiceStatusCallback: params.voiceStatusCallback,
       },
     );
 
diff --git a/packages/server-client/lib/client.ts b/packages/server-client/lib/client.ts
index 82614d82..e47a3bb2 100644
--- a/packages/server-client/lib/client.ts
+++ b/packages/server-client/lib/client.ts
@@ -215,14 +215,14 @@ export class Client {
    */
   async sendFormSubmitRequest<T>(
     url: string,
-    payload?: Record<string, string>,
+    payload?: Record<string, string | undefined>,
   ): Promise<VetchResponse<T>> {
     const request = {
       url,
       method: HTTPMethods.POST,
       type: ContentType.FORM_URLENCODED,
       headers: { Accept: 'application/json' },
-      ...(payload ? { data: payload } : {}),
+      ...JSON.parse(JSON.stringify((payload ? { data: payload } : {}))),
     } as VetchOptions;
 
     return await this.sendRequest<T>(request);