Help with a personal debt please

15th September, I did a council house swap, now the lady who I swapped with, the area I really wanted and its very very rare for a council house to come up in that area...anyway I will get to the topic in hand... she was selling her sofa, bed and a few other bits, it was very precarious where she was calling all the shots on the swap (obviously we were desp to get into the house.) We work hard but don't have a lot of money, we have 3 kids!! ... anyway we agreed to buy her sofa (she asked £700, she said it was only 6 months old, cost her £2k and literally as new) we saw it when we visited but it wasn't then we were looking at the sofa to buy (obv looking at the house in a whole)... we said yes that would be lovely as we would have had to buy a new sofa anyway and THOUGHT that was the going rate for second hand sofa... after a few weeks I thought how are we going to find the money for it as my partners job didn't pay his wages (due to bumpy going to administration/getting bought by another company) so we struggled even more, I text her saying would you accept less for the sofa as I had done research and second hand they go for around £300/£400. She got cross and said no way, they aren't the same one, hers was bigger/better etc... (we weren't over there in the new house so couldn't see it, and she had a go at us saying she is doing us a good deal blah blah and that she is happy to accept a payment plan so we can pay off the sofas.....We felt obliged to buy, basically we were being 'yes-people' to get over there in the new house!! Anyway... day of the move, we both swap houses, all we had money wise was £400 so gave her that. We moved in and was busy settling kids into their new school and sorting the house out. On inspecting the sofas, they aren't worth £700, they aren't 6 months old as a neighbour told me that this womans husband brought them from his flat when he moved in (they had been there 4 years, so basically the sofa must be 3/4 years old) I can probably do more research to see what age they are!! ... the seats under the cushions have collapsed in where the corner bit, you sit on and it leans where it has gone in, Also one of the scatter cushions has split and been repaired!!! I am really gutted, I feel awful that I have been ripped off to the tune of £700 and we still owe her £280, I don't know what to say to her as she is horribly confrontational!! How do I stand legally?! Do I stand anywhere seeing as its been a while.. we are stuggling so bad with money and my children come first, I just don't know what to do.

The bed was also broken although useable but that was £150 and we sold her our 7ft table for £250 so that took money from the bed and some of the sofa. We also bought a curtain rail and 2 floating shelves from her for £30! Oh and also a broken garden set for £50.... mugs?! yes we were

I hope this makes sense, I have just typed and typed and am really upset and stressed with it all!