I would take test #2 (which will not be affected by this mishap) - that will be your 100% reliable test.
Then, you can you do a few things. One - you can reset the question banks and take the first test. if you run into a question you have solved already/seen already, then pick the same answer choice you did last time and wait 2 minutes for quant or 1 min:45 secs for verbal. In GMAT Prep it is not as much knowing the answers as rather the extra time that inflate the scores, so you must wait the time as you are taking the test (this is still not accurate since you will be resting here and there and that's not realistic but it is as good as you can get).
The GMAT Prep question bank is pretty large - more than a thousand questions between Q and V, so there is a chance you won't see that many repeats so your score won't be throw off all that much.
There are of course EP1 and EP2 with 4 additional tests....