Oak Furniture Land Refund Problems

Hi,
Would appreciate some advice on an issue I'm having with Oak Furniture Land regarding a refund for some faulty goods. I bought furniture back in the Summer, which over a few months cracked and warped and following inspection by their representative, they agreed to a full refund. I have two questions on the back of this:

1/ When they came to collect the furniture, the delivery guys (part of same company) did a lot of damage to my house, ripped wallpaper, dented plaster and woodwork and damaged carpet. The hallway now needs redecorating as the wallpaper was so badly damaged. I noted all this on the delivery slip which the driver took, immediately phoned the company, and sent them photos of the damage as requested.
Now they say the drivers deny causing the damage, and are refusing to pay for repairs. Do I have any right of redress here??

2/ When the refund cheque came, they had issued 2 identical cheques in error, i.e. double the amount. I only cashed one, however the company realised their error a few days later and cancelled both. They have issued a new cheque LESS the £30 cost of stopping the first two!! I'm livid that they are charging me for their admin error. Do I have any rights to claim this back? They claim they thought I would cash both, therefore needed to cancel both, but since I had only ever attempted to cash one of them I do not see how they can claim this. I know its only £30, but still a fair amount of money.

Would really appreciate any advice here, as Oak FL have basically told me to get lost, and take it to court if I want my money back or costs for the damage in the house. I'm a bit nervous about loosing even more money going down the small claims route.

Thanks for your help!