Overrun natural corks

Over the past few months, I have been opening bottles of my 2011 Rhode Island Cabernet Franc/Merlot blend.  I bottled this about 1 year ago using overrun corks from More Wine.  I have been disappointed in these corks for one reason, disintegration.
The overrun corks were about 22 cents apiece and represented a good value.  I had been looking for alternatives to the Altec/Reference/DIAM II corks since they were becoming increasingly hard to find.  I have always been impressed with the Altec corks, since I have bottles that are 6 years old and no problems.  I have never had any leaking and no problems with cork taint.  However, I could not find them anywhere, so as I was making an order for supplies for 2012, I made the leap to overrun corks.  I had no problem with the corks themselves.  They did not require soaking and came in a sealed bag.  They all inserted very nicely and after 4 days, I put them on their side in the cellar.  I have not had any leakers or any other issues.  The problem I have is when I try to take them out.  They pretty much disintegrate when I try to remove them.  When the screw goes through them, they fall apart.  I have been careful not to punch through the cork, so I have as yet not put a large amount of cork in the wine, but it is only a matter of time.  I have been disappointed with the quality of these corks.  Now, I do know that natural corks will tend to fall apart as opposed to agglomerated corks, but this is only after one year and is pretty bad.  So, I think I am done with natural corks.  I have luckily been able to find some additional Diam II corks from a local supplier.  I don’t know why they have become so hard to find as I believe they are an excellent cork.