Sorry to hear about your failure, it now does seem like I've read about a lot of failures of the inverter. I actually thought high quality parts was the strong point of the Titan. Hopefully they've rectified this problem.
Actually just receive my Titan back today from being repaired. Total turn around was one day shy of 2 weeks. I've reconnected the Titan up to the 4 batteries and all seams to be working just as normal. I was told that the inverter and some sort of input controller was replaced.
I was also told (assured) that this would not happen again (another manufacture or better parts???). I tried to press as if new(er) parts were installed and was told no, but the parts that were replaced were new.
I think playing nice with them will go far and because they seem to be a family type of operation that they will do the right thing in the long run...yet very concerned that I spent a lot of money on the Titan and 4 batteries for long term dependability and safety. I've only had my Titan for 14 months and expected it to last longer that 1-2 years.
Please keep in touch, so we can exchange notes.