diff --git a/config/default.js b/config/default.js
index 2b5ca7ba..1a3090bf 100644
--- a/config/default.js
+++ b/config/default.js
@@ -40,7 +40,7 @@ module.exports = {
 
   TOPCODER_USERS_API: process.env.TOPCODER_USERS_API || 'https://api.topcoder-dev.com/v3/users',
   // the api to find topcoder members
-  TOPCODER_MEMBERS_API: process.env.TOPCODER_MEMBERS_API || 'https://api.topcoder-dev.com/v3/members',
+  TOPCODER_MEMBERS_API: process.env.TOPCODER_MEMBERS_API || 'https://api.topcoder-dev.com/v5/members',
   // rate limit of requests to user api
   MAX_PARALLEL_REQUEST_TOPCODER_USERS_API: process.env.MAX_PARALLEL_REQUEST_TOPCODER_USERS_API || 100,
 
diff --git a/src/common/helper.js b/src/common/helper.js
index 0ce11905..e68e5c58 100644
--- a/src/common/helper.js
+++ b/src/common/helper.js
@@ -1304,13 +1304,10 @@ async function getMemberDetailsByHandles(handles) {
   }
   const token = await getM2MToken();
   const res = await request
-    .get(`${config.TOPCODER_MEMBERS_API}/_search`)
+    .get(`${config.TOPCODER_MEMBERS_API}/`)
     .query({
-      query: _.map(
-        handles,
-        (handle) => `handleLower:${handle.toLowerCase()}`
-      ).join(' OR '),
-      fields: 'userId,handle,firstName,lastName,email',
+      'handlesLower[]': handles.map(handle => handle.toLowerCase()),
+      fields: 'userId,handle,handleLower,firstName,lastName,email',
     })
     .set('Authorization', `Bearer ${token}`)
     .set('Accept', 'application/json');
@@ -1318,7 +1315,7 @@ async function getMemberDetailsByHandles(handles) {
     context: 'getMemberDetailsByHandles',
     message: `response body: ${JSON.stringify(res.body)}`,
   });
-  return _.get(res.body, 'result.content');
+  return res.body;
 }
 
 /**
@@ -1327,17 +1324,14 @@ async function getMemberDetailsByHandles(handles) {
  * @param {String} handle the user handle
  * @returns {Object} the member details
  */
-async function getV3MemberDetailsByHandle(handle) {
-  const token = await getM2MToken();
-  const res = await request
-    .get(`${config.TOPCODER_MEMBERS_API}/${handle}`)
-    .set('Authorization', `Bearer ${token}`)
-    .set('Accept', 'application/json');
-  localLogger.debug({
-    context: 'getV3MemberDetailsByHandle',
-    message: `response body: ${JSON.stringify(res.body)}`,
-  });
-  return _.get(res.body, 'result.content');
+async function getMemberDetailsByHandle(handle) {
+  const [memberDetails] = await getMemberDetailsByHandles([handle])
+
+  if (!memberDetails) {
+    throw new errors.NotFoundError(`Member details are not found by handle "${handle}".`)
+  }
+
+  return memberDetails
 }
 
 /**
@@ -1756,7 +1750,7 @@ module.exports = {
   getAuditM2Muser,
   checkIsMemberOfProject,
   getMemberDetailsByHandles,
-  getV3MemberDetailsByHandle,
+  getMemberDetailsByHandle,
   getMemberDetailsByEmails,
   createProjectMember,
   listProjectMembers,
diff --git a/src/services/PaymentService.js b/src/services/PaymentService.js
index d06ad671..e61a6c34 100644
--- a/src/services/PaymentService.js
+++ b/src/services/PaymentService.js
@@ -153,7 +153,7 @@ async function activateChallenge (id, token) {
 async function closeChallenge (id, userHandle, token) {
   localLogger.info({ context: 'closeChallenge', message: `Closing challenge ${id}` })
   try {
-    const { userId } = await helper.getV3MemberDetailsByHandle(userHandle)
+    const { userId } = await helper.getMemberDetailsByHandle(userHandle)
     const body = {
       status: constants.ChallengeStatus.COMPLETED,
       winners: [{