First, congratulations on having the courage to switch to a related but replacement technology when you realised that your initial market was dying. In fact, your question suggests that you have some understanding of your competitive situation, but are finding that the rules that you were used to when you operated in the mature / declining pager market have changed.

This links to some basic marketing theory: the product life cycle. All products and services have a life-cycle, and there are essentially four stages:

The introduction stage starts with a new product. This is not the same as introducing a new brand or product version into an existing market, but refers to a new product type or category. In your market, the introduction of G3 mobile phones, incorporating PDAs, video, digital cameras and the like would fit. In the first stage, there is relatively slow growth, and few competitors.

The growth stage occurs following market acceptance of the new product category. The growth potential attracts competitors, who often introduce new features as a way of gaining share from the company or companies that first introduced the product. This results in rapid change, with further market expansion. Towards the end of this phase, the rate of growth starts to slow, and you sometimes find that weaker competitors leave the market or get acquired by other companies buying market share.

The maturity stage has fewer but stronger competitors. In the maturity stage, there is little scope for growth, except by taking share from other companies operating in the market, and so the market becomes more stable, dominated by a few strong players.

In the decline stage the product becomes outdated, sales decrease and the product eventually dies. A few niche players may remain serving the market, but the competitive situation is relatively stable and easy to manage.

The pager market is likely to be in the final, decline, stage which is why the change to SMS messaging systems has been a shock. This SMS messaging market is probably in the growth phase, where you encounter many more competitors who are introducing new products.

Customers are also learning about the products and so your experience in a different field may not count for much. Instead, customers want to feel confident that they are buying the most up-to-the-minute technology, so you need to ensure that your products stay up-to-date and include the latest product features. You need to take a much closer look at what is happening technologically than you may be used to.

The next bit of your question asks why you are losing customers. This is relatively simple to solve in theory (although not always in practice). Essentially, you need to conduct a win-loss analysis, looking at the reasons you win customers and why you lose them. To do this, you need to ask them.

When you gain a new client, try and find out who they used before (if anyone) and why they chose you. Don't just assume that it was the brilliance of your sales agent, even if that is what he or she has told you. There can be many other reasons and you need to know them. You can then use the information to help your customer targeting.

You also need to find out why you lost, or failed to gain customers. Again, don't take your sales agent's word for granted. He may be right that the competitor came in with a lower offer. However there could be other reasons that you need to uncover if you are to succeed in the new market. Examples include service levels, perceived quality, technology, and confidence in the product or the sales agent's knowledge and approach.

Win-loss analysis can be conducted internally. However many companies prefer to outsource this kind of work, as there is a danger that customers may not always wish to say the truth to the company directly. The company may also not take a fully objective view when following up wins and losses. Sometimes a more honest and objective opinion can be gathered by using someone seen as neutral by the customer.