Sold me a 6 year old battery as new on bidorbuy

I purchased a Deltec Battery in February 2014 from Umbani Solar on bidorbuy. <br> <br> I received the battery 2 weeks later and my electrician installed it into my intellipower backup power system.<br> <br> From the date that i installed the battery the intellipower unit only gave me about half the of what it should give me. I then bought a second battery from Umbani Solar in May 2014 to replace the other battery in my intellipower 4 so that it could have 2 \NEW"batteries and give me a good backup battery life. This was installed by my electrician and the poor backup life persisted. I basically accepted that the deltec batteries must be a bad quality battery. <br> <br> In May this year the 1st battery stopped working "