Who is at fault-my bank or my travel agent?

On Tuesday I went onto the automated payment hotline of my travel agent to pay �150 towards my holiday. After I had put my card details in it then said it failed to process my payment, but reured me I wouldnt be charged. However it has left my bank account and on my online banking it has shown up today on my account and it has come out, even though my travel agent hasn't received it and it hasn't credited off my total balance. This is the 2nd time I have used the automated hotline and it worked instantly the first time, so now I am concerned I may have lost �150 through no fault of my own. I am unsure who is at fault for this-is it my bank or my travel agent?