The best method for telomere sequencing is the C-strand tailing method. The best company to actually do the sequencing is Fasteris. I can give details if you want. I am in no way financially involved with this company..
There are technical difficulties in seuencing tracts of telomeres that are related to structures formed during the sequencing reaction. I have had success with one company in Switzzerland, Fasteris, Inc. I can sequence short tracts manually use dITP and SSB in the sequence reaction. More details upon request.