There is software, which can allow the blockage of number from further calling and SMS. As it is a Symbian software it only supports in high range mobile phones. As Nokia 2700 is a basic phone, which only supports application and software's of Java it is not possible to install the number blockage software in Nokia 2700 mobile phone.
In addition, upto your question what is the need of blocking one particular number, is the number owner harassing you or abusing you by calling and by sending SMS. If you block that number, you will get calls and SMSs from other number, as availability of new numbers is so cheap now days. You can change your number for to avoid the problem, but is there any guarantee of that person not knowing your new changed number. Instead of thinking about temporary solution, it is better to think about permanent solution. Even though if you contact your service provider office stating your problem they may block that particular number from calling and SMS you, but instead of contacting them, you go and contact your nearest police station stating your problem along with some proofs. Police will definitely teach that person a lesson and that person never ever disturbs you again in future.
There are some things that money just cannot buy, like manners, morals and intelligence.