Repeat sales and customer retention
Most companies spend almost their entire budget on new customers and almost nothing on the ones who already bought and were happy.
Why retention pays better
A new customer needs convincing of who you are and why you can be trusted, which costs advertising, manager time and a first-order discount.
Happy customers also refer others, and referrals carry unusual weight here — many decisions follow a friend's advice rather than a website comparison.
Why customers do not return
Usually forgetfulness rather than dissatisfaction: six months later they cannot recall your company name and search again. Whoever reminds them at the right moment wins.
And a missing thread. If contact ends at the invoice, there is nowhere to return to.
Doing it through Telegram
The saved conversation beats any broadcast. A personal message with a relevant reason — a service reminder, an item they asked about arriving — works far better than a blanket promotion.
The test is simple: is this message useful to them or convenient for you? If the latter, do not send it.