Pacenet Meghbela Broadband [PMPL] — slow speed and frequent connectivity issue

I have been using their internet services since march 2018 and used to have no internet service atleast for two days a week and since the past one year it has become worse. The internet speed has slowed down and also there is no network for at least 5-6 hours and at times for 12 hours at a stretch and this happens almost everyday or every other day. I am getting tired of having to mail them everyday and although the issue is resolved for a while but it happens again and sometimes they don't even care to check or respond to a mail.