Extra bedroom allowance

My husband and I have been receiving ESA Housing Benefit & Council Tax reduction for over 10years. Last year due to a change in circumstances (my husband started to receive his State pension) our claim was transferred to UC and is now in my name because I am only 65, at the time of the transfer in November 2024 we received Transitional protection to protect our existing benefits. In February 2025 our circumstances changed again and I applied for the extra bedroom allowance, at first it was declined but I asked for the decision makers to look at it again and the decision was changed and they agreed to pay the extra bedroom. They said they would make the adjustments and it would reflect in my next payment due on 13/1/26 and any arrears due, would be paid separately, however, my monthly payment hasn't changed and they have said I'm not entitled to any arrears, because we received the transitional protection. I contacted them and said that I understand what the transitional payment is but my claim for the extra bedroom was when we were already receiving UC. The first person I spoke to agreed and said to leave it with them, I had to chase it up and then they said we weren't entitlled to the arrears again. I phoned again and repeated what had already been said, and the guy I spoke to agreed with what I was saying and advised me to say as this was referred back to the decision maker, I wanted to appeal for the arrears to be paid. The position I'm in now is they have said I can't appeal because of receiving the Transitional protection, so Im totally confused, my monthly payment hasn't increased, I'm not entitled to any arrears, so I don't understand the point in applying in the first place. Can you please look at this for me and if possible explain (in simple terms) whether or not I should be receiving the extra payment each month and am I entitlled to the arrears from February 2025. I'm sorry this is so long I wanted to explain fully.I look forward to hearing from you.