Since your support system only allowed to have one chat open at a time, customers (like me) with multiple issues end up in having useless bloated chats where your staff members have a horrible long support case to work on… their responses are in each case related to ALL THE TOPICS that had been discussed in this topic.
There is no way for the customer to close a chat and start a fresh one.
Other companies have a strict „one issue = one support case“ policy.
As it isn’t even possible to separate urgent payment issues and general questions in separated chats or having multiple chat, you should allow customers to just close old chats even if a problem was not solved. That way urgent issues can be treated with a proper attention to it.