Managing contact access by blocking or unblocking users in Teams Free
Hello muqaddas tariq,
I understand how urgent this is, especially when the other person is still sending messages but you are unable to reply.
Please note that this is a user-to-user forum, so contributors cannot access or modify Teams chats. Based on your description, this message does not necessarily mean that the contact has blocked you. Microsoft has documented a Teams Free issue where a chat may display "Wait for [contact] to reply to continue messaging" and prevent you from replying until the recipient accepts the chat request again.
If possible, contact the person through another method and ask them to open the Teams conversation and accept the chat request again. Once the request is accepted, the chat should become available for messaging again. For reference, see: Wait for chat reply to continue messaging error in Microsoft Teams Free.
I hope this helps get the conversation working again soon.