Rude call to existing client

We all get calls from companies we DONT deal with wanting to sell us goods and services. However, when we get a call from a service provider I DO use like RAIN wanting to sell me more services, I find it unacceptable and rude for the caller to end the call suddenly when I say no to the offer. This is not how you treat a client of over 2.5 years. Please advise your call centre to treat customers with respect.