Samsung Star S5233w — SHABBY SERVICE CENTRE WORK

i bought samsung star MODEL S5233W from reliance digital outlet secunderabad on 23 dec 09 and it hanged on 29th dec 09.
could not take it to service centre on 30 th due to bandh.
on giving it to service centre on 31st dec they said it's motherboard needs to be changed and will require 10 days.
today. 15 days after it was given, they are saying that it will require another 10-15 days for mother board change.
it baffles me THE LEVEL OF INAPTITUDE/LACK OF PROFFESSIONALISM.
HOW LONG WILL IT TAKE?
I NEED A CLEAR ANSWER AND NOT THIS REPEATED VISITS TO THE SERVICE CENTRE.
PLEASE HELP ME.
THE NAME OF THE SERVICE CENTRE IS RATNA ELECTRONICS IN CHINOY TRADING CENTRE SECUNDERABAD.
THE WORK ORDER NO IS 9L3107.
MY NAME IS Dr JAYANTI, [protected]