Resign from my tier 2 job before ILR is due

Hello fellow members,
I hope all is good. I really want to thank you all the fellow members for their advice and input into this forum. This forum has helped so many people over the years. I am posting my question below which I help the forum members will be able to help me out.
I am currently on tier 2 visa since December 2011 sponsored by company. I qualified for my 5 year ILR period last November but my company refused to write a letter supporting my ILR application although I made £43000 last year. The reason for this is that the company claims that it involves overtime.
Anyhow I didn't want to persuade them too much as I qualify for 10 year ILR in September this year and my visa expires in October. Here is my question guys:
1. Is my company right in not providing the letter for my ILR on their claims?
2. If i leave my tier 2 job in July this year will I still be able to apply for my ILR based on the 10 year route? I am intending to start a masters course in October this yea and plan on taking couple of months off before starting the course?
Thanks to fellow members in advance

Hi moderators,
I have been employed on tier 2 general visa with my company since January 2012. I was due for a 5 year ILR via tier 2 in December 2016 but my company is not willing to write me a letter conforming that I will still be needed for future employment. With that in mind I am thinking about resigning from my job at the end of march even though my tier 2 is valid till 30 September 2017. I am eligible for ILR on 30th of July 2017. My questions are:
1. How long curtailment leave will I get if I resign from my job in March 2017.
2. Will I still be eligible for ILR in July 2017 if they curtail my leave post 30th March 2017?

Thanks.

1. How long curtailment leave will I get if I resign from my job in March 2017.

Usually 60 days from the date on which employment was terminated.

2. Will I still be eligible for ILR in July 2017 if they curtail my leave post 30th March 2017?

If you leave your employment in March, you must find a new sponsor within 60 days or switch to another category or else your continuous period of stay will be broken.

Thanks Zimba88 for your promp reply. I have few questions that arise from this:
1. How prompt are UKVI to issue letter of curtailment once they receive end of employment notification from my sponsor?
2. Does the period of curtailment given by UKVI count as legal stay towards your 10 year ILR?
3. If I have less than 6 months leave left on my TIer 2 visa would the UKVI still curtail my leave to 60 days or would it to be till the end of my Tier 2?
Thanks a lot for your help on this matter.

So why does your sponsor refused to issue the letter ?

Curtailment is not a speedy process. It will take at least 8 weeks and mote like 14-16 weeks to receive a curtailment letter.
They will issue a curtailment letter up to the point where you still have more than 60 days to visa expiry. In years gone past they had a 6 month window prior to visa expiry, that has long gone.

Does curtailment count as continuous stay - yes.

Be careful with your idea of going to tier 4, things are a lot different now and the university of choice you may find are very particular about issuing a CAS especially if there is a thought you maybe extending your stay for the purpose of solely aging ILR.

Good luck