Servicing of bettery

On tuesday 24/11/2015 i took my car to bettery center Gezina for a routine check up. I did this because i was in the area and havent visited them in a while. first thing to note is that when i got there, the person that was checking my battery did not use the usual equipment to check the battery, he used some small thing i have never seen before since ive been servicing my battery with them.. note: before this my battery never had any problem what so ever. after he did whatever he was doing he told me the battery is in good working order as expected since ive never experience any problem.. the following day my batter starts giving me a problem, i then went to them on friday 27/11/2015 to report this.. they told me the teminal is loose they fixed it and i left.. after a few minutes away the battery does the same thing.. i go back, they then use the usual testing machine not the other that they used on the other day.. they tell me my battery is dead i must replace it. two days after their service gave me assurance that the battery is 100 percent now suddenly i must replace the battery?.. it is not a coincidence and i am not stupid.. is that how you get clients to buy? kil batteries?