UIF - No one to help.

I have been religiously paying my uif and submitting it monthly via email for the last 12 months. I now have received a letter dated the 5th Feb on the 27th Feb giving me 14 days to pay my outstanding UIF or be charged interest. How can anyone do that with the failing postal service currently. 1. My UFILING site has not worked since they changed it last year hence the reason I submit manually. 2. I only ever received one email acknowledging the manual submissions once in the 12 months I have been submitting. 3. I can never get through to the call line and emails are not answered or acknowledged months later. How is it that someone who is making the effort to pay gets penalised when they are not at fault. I really need help getting my ufiling working or getting some way to sort this issue out - So come on UIF - Please help.