They say that a person needs to hear a message 17 times before they even begin to understand it . likely need to use multiple media and touches or attempts at each entry before paying customers . In this case, it is advisable to start with the cheapest media, since each trip to the wallet will generate a cost. If you use the cheapest media first (as long as these media job function email database are not only cheap but also fast and have a good reach) and you make sure to gradually remove paying customers from your strategy , the first customers will only have cost you less, since you used cheap media and not expensive media.
If you start with expensive media, you'll have paid expensive media for every customer, even though some happy customers would have paid you just by receiving a text message, a medium 20 times cheaper than a call with an agent.
To bring things back to the point, let's look at a simple case that only compares two means of contact: SMS and call with an agent .
Let's say the SMS costs you $0.85 MXN and causes 30% of people to pay after the first call, 15% after the 2nd, and 5% after the 3rd, and the call with an agent costs $17 MXN and causes 50% of the people who answered to pay after the first call, 10% after the 2nd, and 5% after the third, we will have the following cases: