The Missing Children Society of Canada (MCSC) says it has lost more than $13,000 in bottle donations in Calgary over the last few months.

The society has bottle collection sites, formerly operated by Child Find Alberta, inside businesses around the city.

The funds raised benefit missing children and their families.

"Individuals have been posing as our drivers and going into those businesses and picking up the bottles before we can go and pick them up ourselves," said CEO Amanda Pick. "This has now resulted in thousands of dollars being stolen from the program."

Businesses taking part in the program should keep in mind that drivers who pick up bottles for the organization wear vests or T-shirts marked with "Missing Children Society of Canada Bottle Program," as well as MCSC name tags.

'It's terrible'

Pick says every dollar helps keep the society's doors open.

"These companies are generously contributing to this program thinking that they are helping to make a difference in the Calgary community, when in fact individuals are stealing that opportunity from us and the companies," said Pick.

"It's terrible."

The thefts were first reported to police in April, 2015, but have been happening since last October.

Calgary police are looking to speak to anyone with information. Contact police at 403-266-1234 or Calgary Crime Stoppers.