Battery problem

[DYGIT]

I sent this to HTC:

Thanks for getting back to me so quickly. A couple of things though:

1. I was told at the Sprint store that they have no available batteries to offer at this time for replacement. So.......
2. It troubles me that you note "use the original wall charger to charge the device for at least and not more than for four hours." Why four hours? Does the charger not shut off or trickle charge once the battery is fully charged? Who is going to watch the charger for that amount of time and make sure that only 4 hours have gone by? If more than 4 hours, what then? Every other phone I have had, did not have a requirement of removing from a charger once it was fully charged.......
3. I have a 2-3 bar signal at my home - the ONLY thing on is my phone - NOTHING ELSE IS ON - the phone will only stay charged for about 1 1/2 - 2 days. This does not fit the stats that HTC publishes for the phone (up to 200 minutes talk time and up to 9.5 days standby time). Something is not correct here and I would like some answers since I have invested my time and money in your company's product. What can be done?