diff --git a/src/Membership.php b/src/Membership.php
index e7a52ee..8a23b0d 100644
--- a/src/Membership.php
+++ b/src/Membership.php
@@ -16,7 +16,7 @@ class Membership {
 	 * Membership constructor.
 	 * Get user data if requested
 	 *
-	 * @param string $user_id
+	 * @param  string  $user_id
 	 */
 	public function __construct( $user_id = '' ) {
 		if ( $user_id ) {
@@ -95,7 +95,12 @@ public function get_subscription_date( $group_id ) {
 	 * @return mixed
 	 */
 	public function get_valid_to( $group_id ) {
-		return get_user_meta( $this->user_id, '_ssc_group_subscription_valid_to_' . $group_id, true );
+		$valid_to = get_user_meta( $this->user_id, '_ssc_group_subscription_valid_to_' . $group_id, true );
+		if ( $valid_to === '1970-01-01' ) {
+			$valid_to = '';
+		}
+
+		return $valid_to;
 	}
 
 	/**
diff --git a/src/Rest.php b/src/Rest.php
index 5ad1913..70f794a 100644
--- a/src/Rest.php
+++ b/src/Rest.php
@@ -136,7 +136,7 @@ public function create_item( $request ) {
 
 				$membership = new Membership( $user_id );
 				// Check if the user is already member of the group, if so, adjust the valid to date
-				if ( ! empty( $membership->groups[ $group ]['valid_to'] ) ) {
+				if ( ! empty( $membership->groups[ $group ]['valid_to']) && $valid_to_months !== '' ) {
 					$valid_from          = $request->get_param( 'valid_from' ) ?: '';
 					$original_valid_to   = $membership->groups[ $group ]['valid_to'];
 					$original_valid_from = isset( $membership->groups[ $group ]['valid_from'] )