Wharfedale bookshelf with Sherwood stereo Amp

[Abhi012]

Hi, I was using Wharfedale towers with this Sherwood Amp for quite sometime. I recently tried to pair this amp with idle lying bookshelfs, but both the speakers stopped playing lower frequencies and are left with very low sounds. Both speakers went off one by one in increasing sound. Any idea what could have gone wrong and what could be done now.