I don't know what to do with this tree. It came with property when I purchased 4 years ago. The first year, it had the best apples ever!! Since then, it has been lumpy, rotten quickly, and/or developed brown spots. The photos are this years so far. Is there something I should be doing that I am not? The tree looks very healthy and has no problem growing. Any help would be appreciated as I have no knowledge on these. Thank you!