Is it possible to buy a replacemen battery for my Garden lin hedge trimmer?

I bought An Aldi Battery hedge trimmer before last Christmas. I have been in hospital at various times from Before Christmas.
I came out of hospital and decided to trim my hedge. You can imagine my frustration when I could not get the battery to hold a charge.
What could I be doing wrong?
The trimmer battery has been charged no more than 9 times.
Regards Maurie