Rain refusing to refund me after cancellation due to poor network

I subscribed to Rain and paid a pro-rata on the 6th of Jan 2025, and the router was delivered on the 10th. I had problems with the network and called several times, but it was still so bad that I couldn't work with it as I work from home. On the 15th of Jan 2025, I called and canceled. I received a cancellation email with this Reference Number: ***5. Rain continued to bill me for Feb, even though I have canceled and requested them to fetch the router. They only fetched the router after I went on Hello Peter. I was then given a refund for Feb but they did not refund me for Jan. Today I spoke to an urgent named Pravesh who told me they won;t refund me for Jan because I used the data. I then asked but 1. I reported that it is not working, you sent confirmation of the cancellation and did not fetch it in Jan, 2. I did not use it the whole pro-rata period, I used it from the 10th to the 15th and it was very bad, I had to buy my data to work as I work from home and you have recordings of me calling days before cancellation that the network is so bad. After trying to explain that Pravesh an Indian consultant said they wouldn't pay he hung up the phone on me. What pains me I have wasted my time and money calling Rain and they always promise to call me back but they never did. Please check your records and ref number the first cancellation was on the 15th of Jan 2025.