Some Coast Capital Savings customers say the credit union's upgrades to its online and mobile services have made it almost impossible to reliably do their banking.

Three customers told CBC News they've been unable to do basic banking like send e-transfers and use their debit cards after the upgrade, which happened late last year and was meant to increase security.

They say problems logging on to the credit union's website and app have made it difficult for them to pay their rent or their employees, and that they've received few answers from the credit union about when the problems will be fixed.

Tristan Jer has done his personal banking with Coast Capital Savings for the past five years. Banking online and through the company's app was always reliable and consistent before the upgrades, he said.

The problems started around September, he said. After changing his passwords, he found he couldn't log in to Coast Capital's website. Then, the e-transferred rent payment he tried to send to his landlord kept failing. After talking to the credit union, he was able to successfully pay his rent by e-transfer this month.

He still has trouble logging into the Coast Capital's website and does all his banking on the app.

He said he doesn't remember ever having these issues before the upgrades. He said calls to customer service have not helped, and he has received no communication from Coast Capital on what went wrong and whether the issues will persist.

"I'm always very kind of hesitant and a little bit nervous when the first of the month comes around and I go to do an e-transfer for my rent and I'm like, 'Oh, is it going to go through, am I going to get the error, is it going to crash, is the app not going to work, what am I going to do?'" he said.

"The upgrade was done late last year … they should be well past this now."

Craig Patterson says he gets this message every time he tries to transfer money on the Coast Capital Savings website. He said he never had a problem doing online banking with the credit union until it did security upgrades to its website and app. (Supplied/Craig Patterson)

Chrissy Moore had similar problems that started before Christmas. When she tries to send or receive e-transfers, she says she receives error messages. Her debit card also doesn't work — she said it's been declined at least five times for no apparent reason, leaving her in the lurch at restaurants and gas stations.

"I can't be sure that when I go out I won't be embarrassed or not be able to pay for something," she said.

Moore said she has called, tweeted at and gone to Coast Capital for help but was told by the credit union that there wasn't anything wrong on its end.

Small-business owner Craig Patterson is also frustrated.

Patterson started his business account with Coast Capital Savings in 2013. Three weeks ago, he noticed he wasn't able to send e-transfer payments to employees through the credit union's desktop website. The only way he can send the e-transfers is through its app, which he says is glitchy.

The last straw for him was when he received a "random" charge on his account in February and struggled to get answers from customer service representatives.

He said he's lost trust in Coast Capital.

'There are some issues to work through': Coast Capital

In an emailed statement, Yana Melnichuk, vice-president of digital experience and digital banking, said the issues reported by some of its customers are not widespread and affect a "very small percentage" of its 200,000 members who are using the new digital banking platforms.

Bill payment issues are "very sporadic and intermittent," and e-transfer performance issues are isolated and stem from several third-party vendors, Melnichuk said.

"As would be expected with any platform change of this magnitude, there are some issues to work through as members become familiar with the new system," Melnichuk said.

"However, we recognize that we have fallen short on meeting the needs of those members who have reached out to CBC to express their frustration. For that, we apologize and will reach out to each of them to hear their concerns and find resolution to their ongoing issues."

Coast Capital Savings said it is regularly implementing improvements to its digital services and that anyone who continues to run into issues can contact them by email or by phone.

Patterson said communication with customers should have come sooner. Now, it's too late.

He plans to switch to another credit union or bank.

"If you don't have trust in a financial institution being able to handle your money, that to anyone is concerning," he said.

"I think Coast Capital is really going to have to invest in its technology if it's going to want to keep consumers."