Cannot get money back that I am owed

Shermanator

Sorry if this is posted in the wrong place !

I live in a block of private shared ownership flats and pay a monthly service charge to the management company depending on how much of the flat I own. I used to own 50% and in October purchased the remaining 50%. The management company continued to charge the full rate and I only realised 2 months ago.

I have since had this reduced but they have not refunded me for the months that I was overcharged, this is about £300 I am owed. I have chased and chased and constantly get fobbed off. But I did receive a letter 1 month ago stating that I was overcharged, the fee has now been reduced and they will pass it over to the accounts "team" to get a cheque out to me for the difference. I still haven't received anything and call about twicw a week

What is the best course of action from here....(short of going into the office and creating a scene, which would have been done if I didn't work all day everyday!)

I am considering small claims court but don't want this to end up costing me....and also, was considering the threat but don't want them to call my bluff !!

Thanks and sorry for the long story :-)