sorry to read about your troubles. I do not have a weekend contact in Marineland but I do have a contact in the company. To be honest with you I don't see them compensating you for the loss of livestock or anything beyond a heater replacement. For what its worth I have never been a fan of those heaters. I suggest talking to the shop owner or manager you bought the heater from, as they would be able to deal with the company for you.
p.s.
Large water changes, lots of carbon, poly or purigen would be the game plan. Let me know if you need any help