Cancellation of membership problems

We had a membership with VHI (Vacation Hub International). The payment of membership fees entitled us (according to VHI) to really great deals on holiday packages, and support from their staff, but after paying for some time we realised that the accommodation rates are really not that special, and we only ever did one booking during that time, and also at a pretty standard rate – I cannot say that I feel that we received special treatment. This being said – this is not my problem – I am only putting this down as background information. My actual problem is that I gave instruction for the immediate cancellation of our membership on ***3 via email. I explained that we did not benefit from this agreement, and I wanted to end it. I then received a phone call on the 13th of September 2023 (after I sent a 2nd mail to ask for feedback) trying to convince me not to cancel the membership, mentioning that I would be losing out on a cash back bonus – but I then again in writing confirmed that I wanted to end my membership. I then went ahead and cancelled the debit order with my bank. Then on the 8th of November 2023 I received a statement showing that there was now 2 months debit order outstanding. I then paid the instalment that would have been due for end of September – because I gave notice in September, and I was willing to accept that maybe the September instalment might have been due – but definitely not the October instalment – how many months MUST I give notice? Then they insisted on the October instalment as well – which I then paid – but still now, they are only willing to cancel the membership after the end November instalment is paid, because they did not see on their records that I paid the October instalment on the same day I paid the September instalment? I received a SMS demanding overdue money on the 23rd of November, even after I paid the relevant amount on the 8th already. They keep on harassing me for just “one more month” “one more month” instalment? I gave very clear instructions on the 8th of September 2023 – we are now at the end of November – and they have still not cancelled my membership. I do not feel that this is fair – and I also do not appreciate the constant notifications.