Resignation Refused

Hi All

I'm hoping one of you can help me

I have been in a new job for approx 4 weeks and last week I decided to resign, the commuting was too expensive from my home to place of work and I was also promised I would be given car parking permit etc then discovered there was a 12 month waiting list for these.

Last week I was off for 3 days as I had a sickness bug (I work in a management role as a food handler) so I have to give 48 hours clear before returning to work and I submitted a Self Cert to cover this.

On Thursday I submitted my resignation explaining my reasons why and wishing the company all the best etc and offered 4 weeks notice as per the terms of my contract.

However, since then my employer has refused the resignation and verbally told me that I have to attend a Disciplinary Meeting tomorrow for the absence last week and told me that during that meeting I will not have my probation period extended, this means that instead of me working 4 weeks notice, they instead only have to give me 1 weeks notice pay
Is the employer legally allowed to refuse my resignation? In addition to this, they are now saying that, during my induction week, I do not get paid 100% of my salary because that is a shorter working week than what is in my contract – this was not my fault and they are now withholding % of pay for that week.

Thanks in advance for any help