Jewell Cichlids Attacking And Eating Other Fish - Help!

I bought two jewell cichlids for my community tank, having read up on them and believing they would be a decent addition. But while my stockist advised that they can be territorial and aggressive he didn't tell me they would eat smaller fish! They've now wiped out about ten of my cardinal tetras (which I bought at the same time incidentally - no warning about that) which have disappeared without trace and presumably been eaten. As if that's not bad enough they're also taking chunks out of the tails of my salt and pepper platys - one is already dead. Are they likely to keep up this behaviour? I'm unsure whether to just remove them or alter the balance of the tank in respect of the fish I already have. The others are an albino shark, three red phantom tetras, a couple of barbs and two bristlenose plecs. So far it appears the remaining fish have been spared these kind of attacks.
Any advice gratefully received.

Stuart

Thanks. It's plain now i've made a mistake with these fish. Surprisingly, one of the barbs has now been attacked when I thought the remaining bigger  fish had been spared. The cichlids are a pair - a male and a female. I suspect the male is the more aggressive. Would it be an idea to just remove one? I'd be reluctant to rehome both.

Yeah, I think i am going to have to move them on. Frustrating. I may contact the shop to see if they'll take them back. Incidentally do you think I have a case for saying they were effectively mis-sold - therefore potentially getting my money back? They were bought at the same time with platys and cardinal tetras, but I wasn't warned this was an unsuitable combination...