Magnat Monitor Supreme 5.1 + Magnat Quantum Center 67

Hello,

I have a 5.1 speaker Magnat Monitor Supreme ...
Front left and right = Magnat Monitor Supreme 2500
Rear left and right = Magnat Monitor Supreme 1000
Center front = Magnat Monitor Supreme 250
(AV-Receiver Yamaha RX-V673 = http://de.yamaha.com...x-v673_g/?mode=model)

The Supreme 250 does not work, it is broken during a 5.1 movie (Blu-ray volume on average)
It lasted ONLY 4 months, I am very disappointed reliability!

Now what to do:
a) Magnat Monitor Supreme 250 ---> Magnat Quantum Center 67
And keep the Supreme Monitor 2500 and 1000?
Homogeneity?

b) Take another speaker in the center of Magnat?

c) resume 1x Magnat Monitor Supreme 250?

Thank you in advance

PS: sorry for my bad English (Google Translate :/)