By Panarat Thepgumpanat and Chayut Setboonsarng

BANGKOK (Reuters) - Thailand's consumer protection agency has received about 70 complaints since initiating a probe into aggressive discounting by BYD dealers that has left some buyers feeling they overpaid for their Chinese electric vehicles.

Prime Minister Srettha Thavisin told BYD Chief Executive Wang Chuanfu, who was in Thailand to mark the opening of its first Southeast Asian factory this week and paid a courtesy call to the premier on Friday, to better manage customer expectations about pricing and ensure local buyers were protected.

Wang gave assurances that future pricing would be appropriate and affected customers would receive support, according to a government spokesman.

BYD officials in Thailand and its sole distributor, Rever Automotive, which has a network of over 100 dealerships, did not immediately respond to Reuters emails seeking comment.

The government initiated its investigation into BYD's dealers after a complaint alleged a sales representative had asserted the customer's car price would rise after a discounting campaign ended but instead, the dealership cut prices further.

On social media, some BYD owners in Thailand vented that the deep discounting by the world's largest EV manufacturer had left them feeling short-changed.

"Nothing hurts more than this," said one owner on Facebook, explaining that a BYD Atto 3 car he had bought for 1.19 million baht was now selling for 859,000 baht.

Another aggrieved owner posted a video of himself scribbling disparaging remarks about BYD with a thick blue marker on the hood of his EV, including: "I am never buying this car brand again."

Rever's website on Friday showed some models are currently being discounted by as much as 340,000 baht ($9,300).

Passakorn Thapmongkol, a senior official at Thailand's Consumer Protection Board, told Reuters that the agency had met with Rever officials and asked for documents related to the discounting scheme.

"More customers are gradually coming in to file complaints," he added.

Thailand is BYD's largest market outside China and key to its plans to expand globally - particularly in the wake of 17.4% tariffs imposed on the automaker by the EU.

The Chinese automaker commanded a 46% share of Thailand's EV segment in the first quarter and is the third-largest player in passenger cars, according to research firm Counterpoint.

($1 = 36.5700 baht)