Problems with new replacement DC600

Hi there, Bubbles hubby here

Sorry we haven't been around much lately, but we are about to go on our only dive holiday this year and have been having severe problems with our new replacement Sealife DC600 (which was sent as a replacement for a jamming DC500 at the start of the year).
I hate to say it but overall this one is worse than the old, at least that only jammed occassionally - the new DC600 won't focus on anything indoors or close-up out of doors even in daylight! Eveything is very fuzzy or blurred other than some landscape shots.
Other than in outdoors landscape mode (which seems to work OK) it can't focus on anything when we try to take a picture. Even when we set it to Programe A/E mode with auto flash (as Sealife US technical support suggested when we Emailed them about the problem) and auto flash, leaving the camera to work things out for itself, it still gets everything badly fuzzy and blurred.
Case in point we have been experimenting with a large teddy bear, taking pictures of it from different ranges (12 feet down to about 3 feet). None have been in focus although some are clearer than others. What is incredible is when you first switch the camera on from cold, the bear is nice and clear in the viewfinder/monitor but when you press the shutter to take the picture, you can actually see the image going fuzzy and blurred before it fires!
Using the w/t telephoto to zoom in and out on any subject (eg pet dog) only seems to confuse the camera even more as the pictures go even more fuzzy and blurred. Sometimes though we have noticed that at around x3 (the normal optical zoom max) it does focus but then seems to lock on this particular length and won't unlock, even if we play around with the w/t and end up moving the camera back and forth in distance from the subject until it eventually comes into focus in the viewfinder/monitor. Obviously it has locked to one particular focus and won't change (the only way out when it has completely locked is to switch it off and wait a few minutes, when we switch back on everything seems in sharp focus in the monitor until we try to take a picture (at which point the image in the monitor goes all fuzzy again)!
I honestly don't know what we should try next Any suggestions would be gratefully appreciated. Sealife have been very helpful with messages back and forth but nothing they have suggested (other than advice on getting decent long-dsitance landscape shots providing we don't touch the w/t zoom) has worked.
We are about to go on our only diving holiday at the end of the month to Mexico so there isn't much time to get it sorted out - any helpful hints or suggestions would be greatfully accepted