Answer:
The manager must first interview the representative and ask him about the procedures that he followed in order to make the changes that affected the client's account. The manager has to find out if the representative followed the company's procedures correctly and if the client was aware of the new charges and associated risk. He should ask the representative to hand over any emails or paperwork signed between him and the client.
If the representative followed the procedures correctly, the client's claim s baseless. But if the representative acted improperly, then the company must take immediate action to correct things before the client decides to sue the company.