Hi welcome to Fish Lore
I'm really sorry your fish aren't feeling well. We know how upsetting it is.
Do you know how low the temp went while they were without a heater?
How quickly was it raised once you got a new heater?
What size tank are they in?
Do you know your readings for ammonia, nitrite, and nitrate?
I'm sorry for all the questions, the answers might help the members figure out what's going on.
Also, Fish Lore is a public forum and easily accessed through search engines. For your safety and privacy it would be a good idea to change your user name to something other than your e-mail address.
Here's how to request one:
How Do I: Request NEW UserName
I don't know enough about your type of fish but the members have a wide range of knowledge, I hope they can help.
Good luck, I hope they feel better soon.