Advice needed on taking a company to the small claims court

Hi Guys this is the situation :-

I took 2 cashback mobile deals out with the same company (who shall remain nameless for now) lets call then Company A. Both phones arrived on the same day, one was for me the other for my wife, both phones are on the same network. When I sent the cashback documents in I checked the Ts & Cs on my paperwork and assumed that it would be the same for both phones / deals. I then got 2 letters from Company A stating they where rejecting both claims because I hadn't included some of the required paperwork, Document A. At this point I re-checked the Terms and one set does say to include Document A, the other set doesn't. Unfortunately I had only read the Terms that do not say to include Document A and as such did not send this in.

I have written to them with a copy of the Terms that don't method Document A and have said that I will take action against them in the Small Claims Court unless they reply within a certain time.

They have not replied to my letters and I now need to start the Small Claims Court action, how do I do this ?

The other question is, how is the court likely to view this situation, I was sent 2 different set of Terms, but only realised this after sending the claims in. I think its reasonable to assume that both sets would have been the same, unfortunately the Terms I checked / referenced when sending the claims in seem to be an older version that I can only imagine I was sent in error.