A truly terrible customer experience

We bought some dining chairs from Made, which arrived in good time. We had to assemble them ourselves and it soon became apparent that they were broken; the screws for the backs wouldn't screw in. We contacted Made and they offered us £30 compensation (pitiful amount really considering that the 4 chairs cost nearly £500)! We said we would take the comp and use it to try and fix the chairs. We attempted to fix them with glue, however the back of 2 of them still kept falling off! I again contacted Made, expecting that as a large company they would have some level of customer service.... I was told that because we took the £30 comp we would not be able to return the chairs! Even though they were completely faulty! We would never have taken that tiny amount of money had we known it meant that we couldn't return the items. They also charge the customer for a collection!! Which is absurd. Would avoid at all costs. Expensive products made cheaply.