ILR (TIER2ICT to TIER2GEN case) absence & emp letter??

[pacificmist]

Hi,
I am planning to apply for ILR in Jan'2015.
Below is my visa history and my absence history:
Current date to Jun'14 - Absent for 57 days (VISA TIER 2 GENERAL current employer)
Dec'13 - Jun'14 - 0 absence (VISA TIER 2 GENERAL previous employer 2)
Dec'12 - Jan'12-Absent for 33 days (Visa TIER 2 ICT by previous employer 1)
Dec'11-Jan'11- Absent for 93 days (Visa TIER 2 ICT by previous employer 1)
Dec'2010-Jan'2010 - Absent for consecutive 152 days (Visa TIER 2 ICT by previous employer 1)

I think my absence is ok as none of them is exceeding 180 days at once.
I have 2 questions
a) I changed from TIER 2 ICT to TIER 2 General in Oct'2013. I got my TIER 2 General on 21'Oct 2013 and then I joined the new organisation on 14'Dec 2013. So doest that break the continuous period of 5 years?
b) from Jan'2010 till Oct'2013. I had made several trips(long term and short term) to UK because of my different assignments. I have tried contacting my previous employers to provide the reference to support the absences but haven't heard back from them. So what to do in this case?