TELUS Neighbourhood

I have Nationwide talk and Text 25 which gives me unlimited calling nationwide. I also see a 15c Promotional Rate in my account. What is that promotional rate used for?

I have a Talk an Text 100 plan that expires in May 2019. If I want to add $10 to my account, they seem to say that it will expire in 30 days. Does that mean that my Talk and Text 100 plan will expire in 30 days instead of the 8 months I have left? If...