Ok so I purchased 3 tv EPs off my iPhone and they showed up in my purchases and they took my cash so why does it keep telling me there's an error down loading it all 3 say it then I click retry and it does the same it's been 3 months since buying them.

Ok so I purchased 3 tv EPs off my iPhone and they showed up in my purchases and they took my cash so why does it keep telling me there's an error down loading it all 3 say it then I click retry and it does the same it's been 3 months since buying them. I push the blue arrow next to them in the apple store and it starts then an error code pops up UNABLE TO DOWNLOAD under that all it says is ("title" is unable to down load at this time with a done option or a retry option and no matter how many times I push retry it say the same and under the bars on the download page it says (download error, tap to retry)also if I go back to the product in store it says it's purchased but says its downloading but it's not what's going on Apple how do I fix this! at this rate I'll see the episodes somewhere else instead of watching the ones I bought witch are starting to seem like a wast of money considering I can't watch what Iv payed for.