Battery drains with in 4 hours, cell gets heated during call

model L6i, still in warrenty period, the main problem is battery gets drained very soon that is with in 4 to 5 hours even after complete charge. mobile gets heated up during call.sometimes the process gets hanged up, i will not be able to do anything for few minutes. gave to motorola service center, after 4 to 5 times leaving in service center they have not solved the problem, they say battery has been changed..but even thaen same problem. pl. assist