Ya know, I don’t think the recharging would have been a problem–these batteries, as versus earlier types, don’t really have a battery memory and, in fact, it is recommended to recharge them when still partially charged rather than to discharge them fully (which is not recommended). Batteryuniversity.com is a good source for battery information such as this.
http://batteryuniversity.com/learn/article/how_to_charge_when_to_charge_table
One thought: are you still within one year of purchase (if the U.S.–2 years if the EU)? If so, you still are within the warranty period and you could telephone SanDisk about the circumstances and the short battery life, and see if a replacement player would be provided to you (SanDisk even covers the postage both ways). if you fall within this, I’d try (and I’d even explain the particular circumstances here).
In the U.S.: 1-866-SANDISK (726-3475). And other SanDisk contact information: http://www.sandisk.com/sandisk-support/contact-us
(Also, note that some credit cards double the warranty period coverage–I try to buy my electronics with a credit card that has that feature.)
By the way, it doesn’t look like the battery replacement is all that hard to do (and conductive epoxy glue is available at electronics stores)–but it istill is something to do.
